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Author Topic:   1995 Evinrude 150-HP Ocean Pro Carburetor Problems with Ethanol
Mike Kub posted 02-10-2014 02:13 PM ET (US)   Profile for Mike Kub   Send Email to Mike Kub  
I have a 1995 Evinrude 150-HP Ocean Pro. We don't get much freezing weather here on the upper Texas coast but this year global warming has skipped us and we have had several hard freezes. The plastic carb bowls seem to have developed leaks. The engine is extremely difficult to start now. I'm thinking that prevents adequate suction to get fuel into the carburetors. Has anyone else had this problem?
OMCrobert posted 02-10-2014 02:31 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
The plastic carb bowls of OMC engines has been known to warp and become out of shape due to the ethanol in the fuel. It is a common problem.

http://www.youtube.com/watch?v=Z3cD2iDxy0E

jimh posted 02-10-2014 02:42 PM ET (US)     Profile for jimh  Send Email to jimh     
I had a 1992 Evinrude 225-HP outboard engine with six carburetors. It ran on mostly a blend of ethanol-gasoline fuel, usually E10. I did not have any problems with the carburetors leaking due to the bowls becoming malformed from ethanol fuel.
OMCrobert posted 02-10-2014 02:53 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I guess if you did not experience it then it must not be happening. Case closed.

Stop lying Mike about your carb bowls warping. LOL.

OMCrobert posted 02-10-2014 02:57 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
Here are several other cases. [Gave links to other websites. Please, if you have information about this topic, just give the information. I am not particularly interested in having a discussion about what some other websites might be discussing. We are discussing this topic here, not somewhere else. If you have information, please give your information, not pointers to other websites. --jimh]
jimh posted 02-10-2014 06:12 PM ET (US)     Profile for jimh  Send Email to jimh     
OMCRobert writes in reply to my posting by making a rather bizarre conclusion:

quote:
I guess if you did not experience it then it must not be happening. Case closed.

I answered the direct question that was being asked. Let me repeat the question that was asked of me by Mike:

quote:
Has anyone else had this problem?

My reply was to inform Mike that I have not had the problem. I am not sure why OMCRobert has immediately adopted a bizarre attitude about my reply. From what I can tell, apparently OMCRobert has also not had any problem with leaking carburetor fuel, either, as he makes no mention of it happening with his Evinrude engine with carburetors--well, I guess I am assuming OMCRobert might have an OMC engine with carburetors, but I am really not sure about that, either. Perhaps he has no experience with OMC engines. Who really knows?

However, very strangely, he then gives links to discussions on other websites where apparently other people report problems. This seems to be an immediate contradiction of his earlier statement that "it must not be happening." I really don't understand this reply at all.

Also, I am really not very interested in hearing second-hand or third hand reports being discussed on other websites. The actual purpose of this thread is to have a discussion on this website on this topic. If you have experience with an OMC engine with carburetors, please let us know if you had problems with the carburetors leaking.

To get back on the topic, I have to further add this note. For the several years that I owned the 1992 Evinrude V6 engine, I ran it just about exclusively on fuel that was a blend of ethanol and gasoline. I went to great lengths to keep the carburetor bowls full of fuel, too. When the engine was put away for storage, I would keep the engine in the operating position so that fuel would not drain from the bowls due to gravity and being tilted up. I also would work the primer bulb to make sure the carburetor bowls were filled with fuel. I did this because I found the engine started more easily if the carburetor bowls were full of fuel. I never noticed any leaking of the carburetor bowls.

That is just my first hand experience, based on running a similar engine for about four years. I have no idea if my experience presents the normal experience or the exceptional experience. Apparently my experience seems to be something that OMCRobert thinks should not be presented here, and instead the experience of other people who are not participating in this discussion must trump my experience because they reported it at some other time on some other website. Sorry, but my first-hand experience is directly on the topic. I am not going to disqualify myself from participation in the discussion.

sosmerc posted 02-10-2014 06:22 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
I have experience leakage issues with the plastic carbs the the V6 Fastrike and Eagle models. In fact, I have a customer waiting for me right now to give him a call and come in to have all of his [engine's] carburetor bowls replaced. In his case, there is a steel ball used to plug a drilled passageway in the bowl and some of the balls were leaking. One even fell out, causing a major leak. So yes, the [leaking of some OMC carburetors] is real.
jimh posted 02-10-2014 08:30 PM ET (US)     Profile for jimh  Send Email to jimh     
Sosmerc--I think the model you mentioned is the 2.6-liter V6. My engine was the [3.0]-liter V6. I wonder if the construction of the carburetor is different between those two models.
jimh posted 02-10-2014 08:37 PM ET (US)     Profile for jimh  Send Email to jimh     
Just to be clear, on my OMC V6 engine with carburetors the fuel would leak from the carburetors on occasion, but only if the engine were tilted up all the way. The tilt allows fuel to drain out of the float bowls by gravity. The fuel did not leak due to some damage to the float bowl housings or gaskets.

Ethanol-gasoline blended fuel has been in use in the Midwest for decades. If the carburetors of OMC engines were affected by ethanol fuel and they all leaked--that is, if this were a common problem--then one would expect that there would be legions of OMC carburetor engines leaking fuel all over the Midwest for the past 15 years. I am sure there are some OMC carburetors that have developed leaks, but I cannot really see any evidence that this problem occurs in a majority of engines.

I don't really see that there is any direct connection established that the cause is ethanol-gasoline blended fuel. Ethanol-gasoline fuel seems to get blamed for anything that goes wrong. Maybe Evinrude just made some lousy carburetors in c.1995 and some of them start leaking about twenty years later. Actually, twenty years is probably not an unreasonable service interval of some gasket material that has been exposed to a solvent like gasoline all that time.

OMCrobert posted 02-10-2014 08:50 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
[Made a minor emendation to my description of my engine in a very rude and hostile manner that is particularly inappropriate. I recommend contacting the moderator, me, via email to discuss this attitude problem.--jimh]
jimh posted 02-10-2014 08:58 PM ET (US)     Profile for jimh  Send Email to jimh     
The older 225-HP Evinrude engines were 3.0-liter. I think OMCRober finally contributed something factual to this discussion. Thanks for that.

OMCRobert--What OMC V6 carburetor engine do you own and operate?

Mike Kub posted 02-10-2014 09:01 PM ET (US)     Profile for Mike Kub  Send Email to Mike Kub     
Thanks guys. The entire carb assembly was replaced 3 yrs. ago. [What] about freezing weather being a possible cause? I am not mechanically inclined. so I have to pay others for these types of services. I was told that the bowls cannot be replaced without redoing the whole carburetor assembly. I love this website and check it about two times a day.
OMCrobert posted 02-10-2014 09:06 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I have owned, operated and worked on them all. Including the older crossflows, v6 60 degree 2.6 liter, 90 degree 2.7 liter Looper, 3.0 liter looper as well as the 3.6 liter and 4.0 liter V8s. Even the rare 3.5 liter racing v8 as well.

I currently have 4 different OMC carb engines and routinely work on Evinrude/Johnson carb engines even today in retirement.

The carb bowl can also be deformed via overtightening as well as the ethanol issue.

I am happy to help.

jimh posted 02-11-2014 08:28 AM ET (US)     Profile for jimh  Send Email to jimh     
Out of all those engines, how many had problems with fuel leaking from the carburetors due to deformation of the plastic bowl as a result of ethanol fuel?
jimh posted 02-11-2014 08:37 AM ET (US)     Profile for jimh  Send Email to jimh     
Bombardier Recreational Products has a great website for parts called

SHOP.EVINRUDE.COM

You can see exploded view diagrams of all engine components, get the part numbers, and see the retail prices. You can usually deduce what parts are available as individual parts and which parts are sold as assemblies.

The FLOAT CHAMBER ASSY is part number 04330000 and costs $22.99.

The GASKET, Float Bowl, is part number 0335070 and costs $13.99.

jimh posted 02-11-2014 08:39 AM ET (US)     Profile for jimh  Send Email to jimh     
I don't think below-freezing temperatures will intrinsically cause leaks in OMC carburetors. If that were happening there would be a lot of OMC engines in the Great Lakes region that would be leaking every winter.
masbama posted 02-11-2014 08:37 PM ET (US)     Profile for masbama  Send Email to masbama     
Just had mine [perhaps means the bowls on the carburetors] replaced last year on a 1998 Evinrude 150 two-stroke-power-cycle outboard.
thegage posted 02-12-2014 11:15 AM ET (US)     Profile for thegage  Send Email to thegage     
I had a 1992 Johnson 90. In 2012 I replaced both plastic float bowls because they were warped and would not seal, leading to fuel leaks and poor running. I did not do a scientific analysis as to the cause of the warpage, so it could have been due to ethanol, high temperatures, or gremlins. Nonetheless, the bowls were warped.

The replacement bowls were aluminum, and easily sourced.

jimh posted 02-12-2014 04:04 PM ET (US)     Profile for jimh  Send Email to jimh     
What would be your source of replacement parts for the OMC carburetors, other than from the OMC successor BRP/Evinrude?
masbama posted 02-12-2014 09:39 PM ET (US)     Profile for masbama  Send Email to masbama     
Guy who fixed mine said this [perhaps means leaking of fuel from the carburetor] is somewhat common in OMC engines because of their choice to use plastic.
thegage posted 02-13-2014 08:37 AM ET (US)     Profile for thegage  Send Email to thegage     
Well, here's one source:

http://www.boats.net/parts/search/BRP/JOHNSON/1992/J90TLEND/CARBURETOR/ parts.html

If you order the bowls what arrives are metal, not plastic.

John K.

Mike Kub posted 02-13-2014 02:03 PM ET (US)     Profile for Mike Kub  Send Email to Mike Kub     
[Mike changed the topic to discuss the cost of new engines. Please start a new thread for that topic. Thank you--jimh].

Are those bowls straightforward to replace or require much mechanical savvy?

jimh posted 02-13-2014 03:40 PM ET (US)     Profile for jimh  Send Email to jimh     
The linked source for a replacement bowl has the price at $134. That is quite an increase in price from the OEM source I mentioned earlier, at $23.
jimh posted 02-13-2014 03:43 PM ET (US)     Profile for jimh  Send Email to jimh     
If plastic were intrinsically prone to leaks when in contact with gasoline, I would expect that all plastic fuel tanks would leak.
thegage posted 02-13-2014 11:48 PM ET (US)     Profile for thegage  Send Email to thegage     
quote:
If plastic were intrinsically prone to leaks when in contact with gasoline, I would expect that all plastic fuel tanks would leak.

I suggest you rethink your comment. It has been suggested not that plastic float bowls themselves leak, but that they warp, which affects the sealing surface, which then leads to fuel leaks. The two things are not equivalent.

quote:
The linked source for a replacement bowl has the price at $134. That is quite an increase in price from the OEM source I mentioned earlier, at $23.

On the same website you linked to the price for the engine I specified is also $134. As I said, for that particular engine they were metal (aluminum), so not surprising that they were more expensive.

John K.

seahorse posted 02-14-2014 10:44 AM ET (US)     Profile for seahorse  Send Email to seahorse     

In the 1995-96 years on the 60° engines the epoxy sealant around the float bowl "BB" that sealed a fuel passageway sometimes seeped fuel if affected by solvents in the gas or from additives.

OMC notified dealers to look for seepage and used a better sealant in later carbs and replacement float bowls. The factory covered all engines in warranty that showed the symptoms and many out of warranty when the dealer went to bat for the customer.

Though not factory approved, cleaning and sealing the area with the flywheel magnet epoxy worked very well and many are still leak-free after 10+ years since the repair.

The 90° block used a different design carburetor and float bowl.

jimh posted 02-14-2014 11:08 AM ET (US)     Profile for jimh  Send Email to jimh     
Many thanks to Seahorse for great information about the occurrence of leaks from the carburetors of particular models OMC V6 outboard engines of a particular manufacturing epoch, and also for disambiguation of the different designs used in different models. This information adds greatly to the understanding of this problem: it seems to be isolated to particular models and particular years of manufacture.

Also, again, thanks to Seahorse for explaining that the root cause of the problem was not due to the construction of the part from plastic, but rather to the sealant material being dissolved. That seems to be an important distinction to be made. Two rather broad statements have been made in this discussion which we now find to be misleading: that OMC carburetors leak because they are made of plastic, and that this problem is common. It turns out that the cause of the leaks are limited to certain models and epochs, and the leaks were caused by a sealant being dissolved by the ethanol-gasoline blended fuel.

OMCrobert posted 02-14-2014 11:13 AM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I believe Seahorse is talking about another situation, as well, with the sealant. The [warping] of plastic OMC carburetor bowls is widely known and documented and affects many years.
jimh posted 02-14-2014 11:23 AM ET (US)     Profile for jimh  Send Email to jimh     
I am afraid that I have trouble accepting that very broad statement, as I had an OMC outboard engine with carburetors, and, as I have already explained, there were no instances of fuel leaking from the carburetors due to use of ethanol-gasoline blended fuel. This tends to conflict with the assertion being made, now for the second time and with increased scope and frequency, that there is a common, unstoppable, unavoidable problem with OMC carburetors using plastic components which will lead to them leaking when used with ethanol-gasoline fuel. As I mentioned already, were this to be true, there would be thousands and thousand of reports about this because use of ethanol-gasoline blended fuels has been common in the upper Midwest for decades, and there are an enormous number of OMC outboard engines with carburetors in use in that area.
OMCrobert posted 02-14-2014 11:33 AM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I first saw the issue several years ago and had an indepth discussion with the service instructor in Sturtevant at school about it.

The theory that we discussed was that older, stale or phase separated gasoline or fuel contaminated with water allowed the engine to get fuel that in theory could be much higher then the 10% ethanol that should have been in the system. We have seen fuel lines and even Pate fuel tanks that are unable to withstand ethanol and it is not impossible that in specific situations the plastic bowls become deformed with higher amounts of ethanol.

I respectfully encourage anyone with doubt to simply google the following terms. You will see dozens of examples.

Johnson carb bowl warping
Evinrude carb bowl warping

thegage posted 02-14-2014 02:09 PM ET (US)     Profile for thegage  Send Email to thegage     
quote:
It turns out that the cause of the leaks are limited to certain models and epochs, and the leaks were caused by a sealant being dissolved by the ethanol-gasoline blended fuel.

Have you held in your hand plastic float bowls on leaking carburetors, then put them on a glass plate to see that they are warped? I have.

Have you bought new gaskets in an attempt to seal the old plastic bowls, only to find that because of the severity of the warpage the new gaskets were not sufficient to seal the bowls? I have.

Have you bought replacement aluminum bowls with new gaskets, checked them on a glass plate to see that they are flat, installed them, and cured the leaks? I have.

Jim, you usually are pretty hard on people using anecdotal evidence from a third party to come to a conclusion. I don't know why you're doing this yourself on this occasion.

John K.

george nagy posted 02-14-2014 02:47 PM ET (US)     Profile for george nagy  Send Email to george nagy     
At least one of the carburators on my 1998 150 oceanrunner is leaking. I will be looking closer at the problem this weekend. 'm not sure if the bowls are warped but the motor is an OMC and at least one carb is leaking. This is the first time in over fifteen years that this problem has occurred. Last July I replaced the fuel/vro pump which appeared to be eaten away by the gasoline as well. I have since been running non ethanol fuel only and will continue to do so unless it is unavailable.
jimh posted 02-14-2014 05:10 PM ET (US)     Profile for jimh  Send Email to jimh     
I give a lot of weight to track record. Seahorse has a really good track record. Seahorse's experience is in contradiction to the theory being proposed regarding there being a common, unstoppable, unavoidable problem with OMC carburetors using plastic components which will lead to them leaking when used with ethanol-gasoline fuel.

I give weight to my own experience. My own experience is in contradiction to the theory being proposed regarding a common, unstoppable, unavoidable problem with OMC carburetors using plastic components which will lead to them leaking when used with ethanol-gasoline fuel.

I don't have any doubt that there are some instances of leaks occurring in OMC carburetors on older engines. Most of the engines being mentioned are over 20-years old. As I mentioned previously, the notion that a gasket or sealant might fail after more than 20-years of exposure to a solvent is not particularly hard to believe.

As for a component failing because it was exposed to an abnormal concentration of a solvent, as has now been added as a requirement for the condition of component failure to occur, I can readily believe that. I don't think that when OMC designed the carburetor they anticipated its use with high-concentrations of solvent like ethanol, and this is particularly likely because when the carburetors were designed they were probably not anticipating use with much of any ethanol-gasoline blends. We have seen that even components designed for modern engines to be used with ethanol-gasoline blends have failed in service due to exposure to ethanol.

I am still waiting to hear from OMCrobert about his first-hand failures on his many engines. I am beginning to wonder why he has not told us about the failures on his own engines, if his theory is correct that there is a common, unstoppable, unavoidable problem with OMC carburetors using plastic components which will lead to them leaking when used with ethanol-gasoline fuel.

jimh posted 02-14-2014 05:44 PM ET (US)     Profile for jimh  Send Email to jimh     
I tend to de-weight the experience of people who are in the repair business when they comment about the frequency of occurrence of certain problems. Let me explain. If you work at a facility that specializes in repair of outboard engines, just about all the outboard engines you will see are outboard engines that need repair. If you were to base your estimate of need for repairs on this experience, you would have to conclude that all outboard engines need repairs. Sampling the frequency at which a particular problem occurs by basing it on how many engines at a repair facility require repair of a particular problem is going to lead to an over-estimation of the frequency of repair of the whole population of engines that need this repair.

The notion that someone who works at a repair shop says they repair a lot of carburetors does not mean that all carburetors will need repair.

If you were to extend the experience of repair technicians to the entire population of outboard engines, you would have to conclude that you would never own an outboard engine because the thing would always need repairs. This is just not the true situation.

I am quite sure that people who work at repairing outboard motors have repaired some carburetors from OMC V6 engines with leaks from the float bowl, but I don't think you can extend that to a generalization that this problem is especially widespread, common, universal, inevitable, or unavoidable.

OMCrobert posted 02-14-2014 09:59 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I never said or implied it universal, inevitable, or unavoidable. That is putting words in my mouth.

I said it was "common". Here are my exact words from the first reply "The plastic carb bowls of OMC engines has been known to warp and become out of shape due to the ethanol in the fuel. It is a common problem."

Seahorse never said a single word about carb bowl warpage, instead he proposed another possibility.

In this thread, I have never said that was exactly his problem but instead suggested it because of my experiences. As I said in a previous post, the theory that we discussed was that older, stale or phase separated gasoline or fuel contaminated with water allowed the engine to get fuel that in theory could be much higher then the 10% ethanol that should have been in the system. We have seen fuel lines and even Pate fuel tanks that are unable to withstand ethanol and it is not impossible that in specific situations the plastic bowls become deformed with higher amounts of ethanol. The reason that I believe that I have never experienced it is because I am very anal about my fuel quality. I drain my tank in the winter, stabilize year round and add Yamaha Ringfree to each tank while using a good quality water separator.

I honestly dont care, I was just making a suggestion and it seems like this thread has become a mission to prove me wrong.

jimh posted 02-15-2014 12:06 AM ET (US)     Profile for jimh  Send Email to jimh     
I am really not on any mission except to get accurate information.

common adjective

a. occurring or appearing frequently

b. of the best known or most frequently seen kind

The real unknown in this discussion is what percentage of all OMC carburetors develop leaks due to warping of the fuel bowl caused by ethanol fuel deterioration of the plastic itself. We have first-hand reports that it has occurred from some and has not occurred for others.

seahorse posted 02-15-2014 07:35 AM ET (US)     Profile for seahorse  Send Email to seahorse     


Gasoline leakage is not the result of a warped plastic float bowl - actual material is called Dupont Minlon

Float bowls are cup shaped and the normal fuel level is below the bowl's gasket and flange surface which is what gets warped. With extreme warpage, the carbs could leak when the motor was tilted up, but they won't in normal operation. Air leakage can result in lean running if the high speed nozzle well gasket area does not seal due to a heavily warped bowl.

The Minlon bowls on both the single barrel and double barrel (crossflow engines) carbs are warped from someone over-tightening the screws. Torque specs call for 18-24 inch-pounds. It is very easy for someone to overtorque them and warp the bowls using a regular handle screwdriver.

Speaking of screwdrivers, most of the Minlon carbs use Pozidriv screws, not Phillips head, though they look similar at first glance. Using a Phillips screwdriver wallows out the screw heads and is a dead giveaway to the carbs being manhandled by the untrained and unaware.

Mike Kub posted 02-15-2014 09:10 AM ET (US)     Profile for Mike Kub  Send Email to Mike Kub     
The original question was: is air leakage sufficient to prevent gas from being sucked into the engine so it will go? Peace
seahorse posted 02-15-2014 10:12 AM ET (US)     Profile for seahorse  Send Email to seahorse     
Mike--There is no choke on those motors, they use an electric primer solenoid to "shoot" gas into the intake manifold for cold starting. Your problem may be lack of fuel pressure, plugged up or restricted primer hoses and (or) fittings, or an inoperative primer solenoid.

See if this helps.

With motor vertical, squeeze primer ball until rock hard, turn key to ON then press in for a count of 5. Continuing to press the key in, turn it to START. Make sure throttle is at idle. An engine in good tune should start within 10 seconds. Be sure that you have a strong ignition system and Champion QL78YC plugs gapped to .030".

Because of the primer system design of shooting fuel directly into the intake, the carbs could be plugged up completely yet the engine will fire up.

To test your primer system, run the motor about 1000 rpm and push in on your key switch. The motor should start to stumble and lose several hundred rpm from running rich with the extra fuel introduced by the primer solenoid. If not, then your primer system is not operational.

jimh posted 02-15-2014 11:46 AM ET (US)     Profile for jimh  Send Email to jimh     
Seahorse--Again, many, many thanks for adding some very detailed and thorough information about the composition of the carburetor float bowls, how they are not warped by ethanol but from over-tightening, and the Pozidriv fasteners used to retain them.

I have a lot of experience with the completely inadequate working of a Phillips-head screwdriver when used with Pozidriv fasteners. I first encountered this about 30-years ago when I began to work on electronic devices manufactured in Japan. They typically used Pozidriv screw fasteners. Trying to loosen these with a Phillips screwdriver was very difficult, and it was often seen that the head of the fastener would be damaged by the Phillips head screwdriver slipping off, exactly as you describe with the carburetors. My many years of first-hand experience with seeing other people try to use a Phillips head screwdriver on a Pozidriv fastener is exactly corollary to yours.

As for starting an OMC carburetor engine in colder temperatures, I can offer my experience with the OMC fuel enrichment system, as I started my OMC V6 engine many times on cold mornings in the northern Great Lakes. When the carburetor is properly primed, that is, the primer bulb has been squeezed and the float bowls are full with fuel, and when the enrichment system is working properly, and when the operator follows the recommended starting procedure as given in the operator's guide, the OMC V6 carburetor engine starts beautifully in cold temperatures.

Unfortunately, the operator often fails to follow the directions. This is perhaps human nature, as everyone thinks they know how to start an engine. But each engine has its own starting procedure, and it should be followed closely. To anyone having trouble starting an outboard engine in cold weather: I really recommend a review the recommended starting procedure and to follow it precisely.

ASIDE to Mike--Your initial article mentioned both leaks and carburetor bowls, so I do not think you can be too upset that leaks and carburetor bowls became part of the discussion.

OMCrobert posted 02-15-2014 12:50 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
The major flaw in the over tightening theory is that it does not explain how the bowls warp when the engine has not been worked on in years. Some bowls will warp when no one has touched them from the factory. I would like to hear an answer to that point.

I proposed the over tightening theory 5 days ago (scroll up and you will see it)in addition to the ethanol theory as well but in cases where no one worked on the engine in years, it does not make sense.

FYI- The correct spelling is Pozidriv (no E at the end). [Thanks; fixed all cases of incorrect spellling--jimh]

jimh posted 02-15-2014 03:35 PM ET (US)     Profile for jimh  Send Email to jimh     
I have to again point out the flaw in the theory that the OMC carburetor bowls will be warped by exposure to the very substance they are supposed to contain, the gasoline fuel, albeit gasoline fuel with some ethanol. If this theory were true, then all OMC carburetor bowls will warp and leak, because all OMC carburetor bowls are exposed to fuel--it is, after all, their very purpose under Heaven to contain fuel for the carburetor to use. We see that this theory is easily disproved because there are first-hand reports (my own, for example) that it has not occurred in all cases.

I suspect that rebuttal to this will be to alter the claim that the leaking occurs only when the OMC carburetors are exposed to fuel that contains an unanticipated very high concentration of ethanol. We can now simplify the theory into a more general one: if you expose any portion of the fuel system of any engine to a fuel that engine cannot tolerate, damage will occur to some components of the fuel system of that engine. This is a better theory than the one that wants all OMC carburetor bowls to leak if exposed to ethanol.

On the other hand, the explanation from Seahorse seems to fit very well with the conditions reported. Let me go over the reported conditions:

--the leaking carburetor problem occurs only on engines of a certain model and certain epoch;

--the leaking occurs after someone has worked on the carburetors. (This was suggested by Mike when he told us his carburetors had been serviced three years earlier.)

--it has been reported by first-hand observation of at least two participants that they have seen Phillips screwdrivers used with Pozidriv fasteners.

All of these reports fit precisely with the explanation from Seahorse about the cause of the problem. A known model of carburetor in a known epoch of manufacturing was assembled with a sealant that was unable to tolerate ethanol-gasoline fuel. The solvent nature of ethanol-gasoline dissolves the sealant. Someone over-tightens the fasteners. The bowls warp. It is a darn good fit to the circumstances.

jimh posted 02-15-2014 03:52 PM ET (US)     Profile for jimh  Send Email to jimh     
OMCrobert now contradicts himself. His first theory was:

quote:
The plastic carb bowls of OMC engines ...warp and become out of shape due to the ethanol in the fuel.

But he now retracts that and insists he never said it would happen:

quote:
I never said or implied it [i.e.,that the plastic carb bowls of OMC engines ...warp and become out of shape due to the ethanol in the fuel] [was] universal, inevitable, or unavoidable.

This seems like OMCrobert wants the theory to work two ways. When OMC carburetor bowls come in contact with fuel containing ethanol they warp and become out of shape (leading to a leak), except when they come in contact with fuel containing ethanol and they don't warp and don't become out of shape (and don't leak).

The first premise is that the leaking is due to deformation of the material as a result of exposure to gasoline containing ethanol. The second premise is the material does not deform as a result of exposure to gasoline containing ethanol. To satisfy both claims, the material would have to behave differently. How can the material know which way it is supposed to react? Doesn't it react the same way all the time? It is just a piece of plastic. How can it know when it is supposed to leak to satisfy the first premise and when it is supposed to not leak to satisfy the second premise?

I don't think the material can do that.

OMCrobert posted 02-15-2014 04:58 PM ET (US)     Profile for OMCrobert  Send Email to OMCrobert     
I never retracted anything.

I was correcting your statement here

"I don't think you can extend that to a generalization that this problem is especially widespread, common, universal, inevitable, or unavoidable." - jimh

I never said any of those and in fact gave logic and reason to why it does not affect each engine. Here are my exact words from the first reply "The plastic carb bowls of OMC engines has been known to warp and become out of shape due to the ethanol in the fuel. It is a common problem." I was correcting your view that I stated it was widespread, common, universal, inevitable, or unavoidable.

Creative editing (only one person can edit) makes it look different.

I encourage any to simply google carb bowl warping. I tried to attach links to pictures of the issue but that was not allowed.

It is not just from over tightening.

Jefecinco posted 02-15-2014 07:40 PM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
I believe most of us have learned over the years that it is very difficult if not impossible to find better information about OMC engines than that provided by Seahorse.

Only a person with a very strong ego or very hard head would attempt to convince this audience that Seahorse is not correct in what he says (writes).

Butch

jimh posted 02-16-2014 11:06 AM ET (US)     Profile for jimh  Send Email to jimh     
No alterations have been made to anything OMCrobert has written, except perhaps to add a missing word that was unintentionally omitted in his original posting or to fix a few spelling errors. The notion that I have altered his meaning by changing what he wrote is wrong.

Let me explain by example:

OMCrobert originally wrote:

quote:
The wrapping of plastic OMC carburetor bowls is widely known and documented and effects many years.

I edited this to read:

quote:
The [warping] of plastic OMC carburetor bowls is widely known and documented and affects many years.

I used the square brackets to indicate I had replaced "wrapping" with "warping". Yes, that does significantly alter the meaning, but I was certain that OMCrobert meant to say warping because he had used that term several times before. Also, wrapping a carburetor in plastic made no sense.

I corrected the spelling of the verb affect without adding square brackets, as it is just a spelling error. I frequently correct many common spelling errors in postings here by many people--even some rather very highly regarded and prolific authors--without drawing attention to it with the square brackets. I don't think I have ever made a big public announcement that someone has misspelled a word, however, doing that does seem to delight a few people.

jimh posted 02-16-2014 11:23 AM ET (US)     Profile for jimh  Send Email to jimh     
A salient point mentioned by Seahorse has been overlooked, and perhaps it warrants more emphasis. He wrote about the problem of the carburetor sealant being "affected by solvents in the gas or from additives." I want to draw more attention to the word additives.

It seem that boaters are prone to brewing their own concoctions of fuel and additives. There are many postings in which various substances are recommended to be added to the fuel of an outboard engine in order to derive some benefit. I find these chemistry experiments with your outboard engine to be risky.

My own practice is to follow the advice of the manufacturer of the outboard engine. In the case of my Evinrude outboard engine, Evinrude recommends only using the fuel additives sold by Evinrude and in the concentrations specified in the directions. Adhering to that advice prevents me from pouring a can of solvent directly into each cylinder or carburetor, as has been recommended by various people as a method of shock treatment.

It is not hard for me to believe that running fuel that has been doctored with all sorts of additives through the fuel system of a 20-year-old outboard engine might be a good way to cause more harm than good.

Tom W Clark posted 02-16-2014 11:27 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
I am reminded of a conversation I had with my own outboard mechanic, Dale, a few years ago.

Washington State started requiring the use of ethanol in its gasoline in 2008. When my boat was in for servicing (and after its first tank of E10) I asked Dale if he had seen many problems with boat fuel systems.

He replied that no, he had not seen any problems that could be directly attributable to ethanol in the gasoline but he had seen some nasty fuel system problems caused (he felt) by too much additive added to the gas.

He talked about one customer in particular who had extensive problems. Dale found the guy had been adding several different fuel additives to his gasoline, for different reasons, thinking he was helping his boats fuel system with his home brew.

Dale told this customer bluntly, to STOP adding all that crap to his fuel. I like Dale; he cuts to the chase.

[ Aside: I have since asked Dale about ethanol related problems. He told me he has started to see some deterioration of plastic/rubber components on some outboard motors that he feels is related to ethanol. ]

jimh posted 02-16-2014 11:49 AM ET (US)     Profile for jimh  Send Email to jimh     
ASIDE: While on the sidebar topic of screw fastener heads, I searched for some confirmation of a story I had previously heard about the Phillips head. The Phillips head screw became popular in automotive assembly line work when power tools came into use. The Phillips is intentionally designed to spill off the screwdriver from the fastener if too much torque is applied. This was useful when power drivers were first being used. The driver would spill off the Phillips head before the fastener could break or strip its threads in the material it was being screwed into because of the abundance of torque in the power tool. See

http://www.acontinuouslean.com/2013/04/05/a-better-way-to-screw/

which cite a Wall Street Journal article on the Phillips screw.

The Posidriv does not tend to spill the screwdriver, and you can really get a very strong grip between the tool and the fastener with a Posidriv head. In electronic components an aluminum chassis with anodizing was often used. The anodizing of the aluminum seemed to act like a thread-locker with steel screws. I often encountered many fasteners which were really stuck in place. If you tried to remove the Posidriv fastener with a Phillips screwdriver, the tool would spill out before the fastener would break loose. If the correct Posidriv tool were used, you could get enough grip or purchase to break loose the fastener.

In modern manufacturing, most of the power tools used are now carefully set for a particular torque maximum, and fasteners are tightened to precise torque limits. This has probably reduced the use of Phillips head fasteners. In automotive production we see that Torx head fasteners are now used, and particularly in any fastener where torque is critical.

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