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Author Topic:   Hard to restart 90 hp Johnson two stroke

klausds posted 09-11-2011 11:54 AM ET (US)
I am impressed with all of the advice shared on this site and hope someone can steer me in the right direction to solve my problem.
I am the original owner of a 1992 Montauk, including a 1992 Johnson 90. Over the years this engine has had a new short block installed (over 13 years ago) and a full carb rebuild shortly thereafter. It has run very well until this season (and may be last year, if my memory serves me correctly). The Pate gas tank was replaced last year and a new fuel line/primer bulb replaced this year. Two years ago, the fuel/oil injection pump was replaced with just a new fuel pump; I now mix the oil and gas.
Cold starts and operation are flawless. Idle speed, in the water and in gear shows 400 rpm on the tach. On the trailer (with the garden hose for cooling), idle in neutral shows about 800 rpm. The engine has about 550 hours on the new block/carb rebuild.
When I stop the motor for more than a few minutes, warm starts are difficult. The warm up lever is often necessary, along with regular use of the push choke. The engine often stalls, or when the throttle is advanced, will die as if starved for air or fuel. The primer bulb becomes firm when everything is cold, but not always when warm. Once I get things running again, everything is fine; idle is sewing machine smooth acceleration is strong and it runs endlessly at top rpm. I have not yet tried any fuel additives/conditioners/carb cleaners, etc. for fear of screwing up something.
Is this just an old outboard acting it's age, do I need another carb rebuild, or can something else be done to improve the warm start hassles? Thanks in advance for any ideas and help.
Tohsgib posted 09-11-2011 12:54 PM ET (US)
Try some ring free or ?? and do a compression test before and after.
PeteB88 posted 09-11-2011 01:22 PM ET (US)
People like Seafoam, Nick's right, again...others do Sal Demercurio's decarb procedure, could be bad gas or it might need a link and synch by someone who knows what's going on. There is also an Evinrude spray product that seems to work great - used it in my weed whacker the other day swear it was given new lease on life.
klausds posted 09-11-2011 04:17 PM ET (US)
Thanks for the tips. I'll try the spray products first. I doubt it's a bad tank of gas, as this has been going on for the entire season. Although, maybe a one time bad tank in the past might has caused a problem.
At least we are nearing the end of the season here and if it needs to sit in the shop, it will be somewhat bearable (except maybe the cost).
Agntvbb posted 09-11-2011 05:24 PM ET (US)
Hard to start when warm might be ignition coil (coils). Have you checked spark?
adlert posted 09-11-2011 10:10 PM ET (US)
That's also quite a low idle speed klausds (the 400 rpm in gear). Probably should be closer to 600-650 in gear when fully warm.
Peter posted 09-12-2011 08:02 AM ET (US)
Did the Pate tank ever have E-10 in it?p If so, I'm wondering whether the carburators need to be cleaned/rebuilt.
klausds posted 09-12-2011 05:27 PM ET (US)
I am getting spark. The engine is always rather quick to fire, just won't run steady until I monkey with it for a few minutes. The old Pate tank did have e-10 in it, but it's been well over a season or two since then and most of the gas I buy still has e-10 (I fill up on the trailer at the local service stations). I do however keep coming back to the carbs (or rings) as the likely culprit.
I found a can of OMC engine tuner in my boat stuff cabinet(It sprays into the carbs via the Preventative Maintainence nipple on the top left of the carb intake cover), which I think I'll try first. Then maybe step up the idle, although it is unchanged for years and things used to run well. Maybe then some carb cleaner.
If after cleaning the rings, then carbs, then checking the idle (and spark for good measure) things still aren't correct, I expect it will be off to the shop for what is hopefully no more than a carb rebuild.
I am not a tech, but in pursuit of other passions I have learned most problems are solved by cleaning things, first taking them apart and putting things back together if necessary. Most of everyone's suggestions point to a similar approach. Many thanks again for all of the help.
A2J15Sport posted 09-12-2011 10:02 PM ET (US)
Welcome to "Ethanol".
The owners of two strokers are looking at annual, if not more frequent, carburetor rebuilds/cleanings.
The two strokes, of old, simply don't like this stuff wer're being fed.
I've been nursing a 1994 Johnson 70 for almost a year now. The adjustments are perfect, the compression is good. All leads (should)to great performance. It will run, for sure, just not like it should/did.
I cannot keep it in tune, no matter what I do.
My only savior, to keep it reasonably good running, has been Sea Foam. I use it in everything.
As a Side note, I switched to a Merc. 60 4-stroke on my 15' Sport. As it turned out, I could not get the deal I wanted on the "regular" 60 and ended up with a "Bigfoot". I'm actually glad about it. Can't wait to install and run.
Having run several Merc. Four Strokes, over the last five years, I was impressed. So-I bought.
Peter posted 09-13-2011 08:05 AM ET (US)
Because you have had E-10 in the Pate fuel tank, which is fiberglass, I wonder whether you have fiberglass resin residue in the carb passages.
adlert posted 09-13-2011 08:50 AM ET (US)
Not wishing to start a fight but I think these statements are incorrect a2j15sport:

Welcome to "Ethanol".
The owners of two strokers are looking at annual, if not more frequent, carburetor rebuilds/cleanings.

I don't think many (with suitable fuel tanks) have experienced these problems. Certainly I have seen no issues in any of my old carbed 2-strokes using ethanol blended gasoline. If anything, the alcohol tends to work as a cleaner.
It has been well established that ethanol + fiberglass tanks is not a health mix however. That's a fixable problem. I would guess that something other than ethanol is affecting your 1994 70 hp.
sdfish posted 09-15-2011 06:16 PM ET (US)
I had issues with my 1984 Johnson 75. It would start fine, cold or hot but would die when put in gear. Did sea foam and OMC cleaner. I needed the carbs rebuilt.
Root cause was debris from degraded fuel lines clogging up the carbs. Check your fuel line and if they are old and soft consider changing them. Then rebuild the carbs.
Eagleman posted 09-15-2011 08:14 PM ET (US)
I've owned a couple of older OMC products and had the same problems. In both situations I installed new quality O.E.M. primer bulbs and installed them in the fuel line so that the bulb was in a near vertical position feeding into the engine. This was a simple solution to a frustrating problem, I'd suggest you eliminate any fuel line orientation other than a vertical positioning into the engine. Worked for me!
klausds posted 09-17-2011 11:28 PM ET (US)
Thanks again everyone. I took the rig down to the river today and treated the engine with the OMC engine tuner. I gave it two treatments before giving things a good run. The idle speed has picked up 50 to 100 RPM. Top speed is up 100 to 200 RPM (and past the 5500 readline-time for a new prop?). The starting problem seems to be generally gone, although I may not know with certainty until I can spend more time on the water. I can say, that for the relatively short running time today (under an hour) things seem to be OK. By the way, I also added some gas stabilizer in anticipation of the up comming winter storage season.
I replaced the fuel line form the tank to the engine earlier this summer; the primer bulb is verticle. The hoses under the engine cover are in good shap and the filter is relatively new. The gas tank is no more than two years old and the fuel pump no more than three. Just about the entire fuel system has been replaced in the last three seasons, but I had never "cleaned" the engine (never means 12 to 15 years, since a new short block was installed). Carbon build up in the cylinders seems to have been the likely culprit.
I bumped into a guy in the parking lot who had just poured SeaFoam into his rig due to similar problems. With todays poor fuel quality, maybe an annual engine cleaning is necessary. I am going to make it a part of my winterization routine.
I think I am good to go for now; at least until the next challenge. Hopefully there will be a few more warm weekends before the season ends.
Tohsgib posted 09-18-2011 10:24 AM ET (US)
I ALWAYS decarbed before winter storage.
aja posted 09-22-2011 02:00 PM ET (US)
Interesting that our '92 Johnson 150 has had similar issues which have gotten worst since the middle of the season as well. Our motor starts fine cold and cruises great, but once warm will idle badly and sounds like it is skipping a cylinder until it stalls. I swapped the plugs and fuel filter which didn't end up having any impact so was thinking I was in for a carb rebuild due to ethanol problems since I have run a bunch of E10 through this engine. If people think this may be something a can of fuel treatment might cure then I am all ears.
adlert posted 09-22-2011 02:17 PM ET (US)
Could be fuel related aja, could very well be ignition related though too. Electrical components frequently first show their weaknesses when warm (or hot). I suggest you check for spark quality when the missing symptoms appear. Various easy methods are available for that task. My favorite technique to use when simply checking for the presence or absence of a spark on a running engine (as opposed to checking spark strength) is to use an inductive timing light. Also make sure it's not past time to replace your spark plugs.
thegage posted 09-22-2011 02:33 PM ET (US)

quote:
I ALWAYS decarbed before winter storage.

Yup, that's the recommendation in the orginal owner's manual. I think a mid-season treatment couldn't hurt, either.
John K.
Tohsgib posted 09-22-2011 03:04 PM ET (US)
aja your engine has the OIS optical ignition, have that checked. Klausds...yours does not have the OIS or I would mentioned that first.
aja posted 09-22-2011 05:57 PM ET (US)
With regards to ignition, I went on a wild ghost chase maybe 5 years back which started with replacing the power packs on the engine and went through all sorts of other things before completely rebuilding the carburetors which solved that problem. With that in mind I am more suspect of the fuel and/or carburetors now but suspect it is worth a check to be sure.
adlert posted 09-22-2011 06:34 PM ET (US)
Yes aja, checking an ignition system is always worthwhile. It's just so damned easy to do, and so absolutely necessary to have working correctly. Whenever approaching an engine running quality problem of almost any type, it is worthwhile first spending a few minutes checking spark presence/quality and also compression. Once done you can really start to home in on your problem and make good decisions regarding how much money and time your willing to pour into the repair effort.

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Author	Topic: Hard to restart 90 hp Johnson two stroke
klausds	posted 09-11-2011 11:54 AM ET (US) I am impressed with all of the advice shared on this site and hope someone can steer me in the right direction to solve my problem. I am the original owner of a 1992 Montauk, including a 1992 Johnson 90. Over the years this engine has had a new short block installed (over 13 years ago) and a full carb rebuild shortly thereafter. It has run very well until this season (and may be last year, if my memory serves me correctly). The Pate gas tank was replaced last year and a new fuel line/primer bulb replaced this year. Two years ago, the fuel/oil injection pump was replaced with just a new fuel pump; I now mix the oil and gas. Cold starts and operation are flawless. Idle speed, in the water and in gear shows 400 rpm on the tach. On the trailer (with the garden hose for cooling), idle in neutral shows about 800 rpm. The engine has about 550 hours on the new block/carb rebuild. When I stop the motor for more than a few minutes, warm starts are difficult. The warm up lever is often necessary, along with regular use of the push choke. The engine often stalls, or when the throttle is advanced, will die as if starved for air or fuel. The primer bulb becomes firm when everything is cold, but not always when warm. Once I get things running again, everything is fine; idle is sewing machine smooth acceleration is strong and it runs endlessly at top rpm. I have not yet tried any fuel additives/conditioners/carb cleaners, etc. for fear of screwing up something. Is this just an old outboard acting it's age, do I need another carb rebuild, or can something else be done to improve the warm start hassles? Thanks in advance for any ideas and help.
Tohsgib	posted 09-11-2011 12:54 PM ET (US) Try some ring free or ?? and do a compression test before and after.
PeteB88	posted 09-11-2011 01:22 PM ET (US) People like Seafoam, Nick's right, again...others do Sal Demercurio's decarb procedure, could be bad gas or it might need a link and synch by someone who knows what's going on. There is also an Evinrude spray product that seems to work great - used it in my weed whacker the other day swear it was given new lease on life.
klausds	posted 09-11-2011 04:17 PM ET (US) Thanks for the tips. I'll try the spray products first. I doubt it's a bad tank of gas, as this has been going on for the entire season. Although, maybe a one time bad tank in the past might has caused a problem. At least we are nearing the end of the season here and if it needs to sit in the shop, it will be somewhat bearable (except maybe the cost).
Agntvbb	posted 09-11-2011 05:24 PM ET (US) Hard to start when warm might be ignition coil (coils). Have you checked spark?
adlert	posted 09-11-2011 10:10 PM ET (US) That's also quite a low idle speed klausds (the 400 rpm in gear). Probably should be closer to 600-650 in gear when fully warm.
Peter	posted 09-12-2011 08:02 AM ET (US) Did the Pate tank ever have E-10 in it?p If so, I'm wondering whether the carburators need to be cleaned/rebuilt.
klausds	posted 09-12-2011 05:27 PM ET (US) I am getting spark. The engine is always rather quick to fire, just won't run steady until I monkey with it for a few minutes. The old Pate tank did have e-10 in it, but it's been well over a season or two since then and most of the gas I buy still has e-10 (I fill up on the trailer at the local service stations). I do however keep coming back to the carbs (or rings) as the likely culprit. I found a can of OMC engine tuner in my boat stuff cabinet(It sprays into the carbs via the Preventative Maintainence nipple on the top left of the carb intake cover), which I think I'll try first. Then maybe step up the idle, although it is unchanged for years and things used to run well. Maybe then some carb cleaner. If after cleaning the rings, then carbs, then checking the idle (and spark for good measure) things still aren't correct, I expect it will be off to the shop for what is hopefully no more than a carb rebuild. I am not a tech, but in pursuit of other passions I have learned most problems are solved by cleaning things, first taking them apart and putting things back together if necessary. Most of everyone's suggestions point to a similar approach. Many thanks again for all of the help.
A2J15Sport	posted 09-12-2011 10:02 PM ET (US) Welcome to "Ethanol". The owners of two strokers are looking at annual, if not more frequent, carburetor rebuilds/cleanings. The two strokes, of old, simply don't like this stuff wer're being fed. I've been nursing a 1994 Johnson 70 for almost a year now. The adjustments are perfect, the compression is good. All leads (should)to great performance. It will run, for sure, just not like it should/did. I cannot keep it in tune, no matter what I do. My only savior, to keep it reasonably good running, has been Sea Foam. I use it in everything. As a Side note, I switched to a Merc. 60 4-stroke on my 15' Sport. As it turned out, I could not get the deal I wanted on the "regular" 60 and ended up with a "Bigfoot". I'm actually glad about it. Can't wait to install and run. Having run several Merc. Four Strokes, over the last five years, I was impressed. So-I bought.
Peter	posted 09-13-2011 08:05 AM ET (US) Because you have had E-10 in the Pate fuel tank, which is fiberglass, I wonder whether you have fiberglass resin residue in the carb passages.
adlert	posted 09-13-2011 08:50 AM ET (US) Not wishing to start a fight but I think these statements are incorrect a2j15sport: Welcome to "Ethanol". The owners of two strokers are looking at annual, if not more frequent, carburetor rebuilds/cleanings. I don't think many (with suitable fuel tanks) have experienced these problems. Certainly I have seen no issues in any of my old carbed 2-strokes using ethanol blended gasoline. If anything, the alcohol tends to work as a cleaner. It has been well established that ethanol + fiberglass tanks is not a health mix however. That's a fixable problem. I would guess that something other than ethanol is affecting your 1994 70 hp.
sdfish	posted 09-15-2011 06:16 PM ET (US) I had issues with my 1984 Johnson 75. It would start fine, cold or hot but would die when put in gear. Did sea foam and OMC cleaner. I needed the carbs rebuilt. Root cause was debris from degraded fuel lines clogging up the carbs. Check your fuel line and if they are old and soft consider changing them. Then rebuild the carbs.
Eagleman	posted 09-15-2011 08:14 PM ET (US) I've owned a couple of older OMC products and had the same problems. In both situations I installed new quality O.E.M. primer bulbs and installed them in the fuel line so that the bulb was in a near vertical position feeding into the engine. This was a simple solution to a frustrating problem, I'd suggest you eliminate any fuel line orientation other than a vertical positioning into the engine. Worked for me!
klausds	posted 09-17-2011 11:28 PM ET (US) Thanks again everyone. I took the rig down to the river today and treated the engine with the OMC engine tuner. I gave it two treatments before giving things a good run. The idle speed has picked up 50 to 100 RPM. Top speed is up 100 to 200 RPM (and past the 5500 readline-time for a new prop?). The starting problem seems to be generally gone, although I may not know with certainty until I can spend more time on the water. I can say, that for the relatively short running time today (under an hour) things seem to be OK. By the way, I also added some gas stabilizer in anticipation of the up comming winter storage season. I replaced the fuel line form the tank to the engine earlier this summer; the primer bulb is verticle. The hoses under the engine cover are in good shap and the filter is relatively new. The gas tank is no more than two years old and the fuel pump no more than three. Just about the entire fuel system has been replaced in the last three seasons, but I had never "cleaned" the engine (never means 12 to 15 years, since a new short block was installed). Carbon build up in the cylinders seems to have been the likely culprit. I bumped into a guy in the parking lot who had just poured SeaFoam into his rig due to similar problems. With todays poor fuel quality, maybe an annual engine cleaning is necessary. I am going to make it a part of my winterization routine. I think I am good to go for now; at least until the next challenge. Hopefully there will be a few more warm weekends before the season ends.
Tohsgib	posted 09-18-2011 10:24 AM ET (US) I ALWAYS decarbed before winter storage.
aja	posted 09-22-2011 02:00 PM ET (US) Interesting that our '92 Johnson 150 has had similar issues which have gotten worst since the middle of the season as well. Our motor starts fine cold and cruises great, but once warm will idle badly and sounds like it is skipping a cylinder until it stalls. I swapped the plugs and fuel filter which didn't end up having any impact so was thinking I was in for a carb rebuild due to ethanol problems since I have run a bunch of E10 through this engine. If people think this may be something a can of fuel treatment might cure then I am all ears.
adlert	posted 09-22-2011 02:17 PM ET (US) Could be fuel related aja, could very well be ignition related though too. Electrical components frequently first show their weaknesses when warm (or hot). I suggest you check for spark quality when the missing symptoms appear. Various easy methods are available for that task. My favorite technique to use when simply checking for the presence or absence of a spark on a running engine (as opposed to checking spark strength) is to use an inductive timing light. Also make sure it's not past time to replace your spark plugs.
thegage	posted 09-22-2011 02:33 PM ET (US) quote: I ALWAYS decarbed before winter storage. Yup, that's the recommendation in the orginal owner's manual. I think a mid-season treatment couldn't hurt, either. John K.
Tohsgib	posted 09-22-2011 03:04 PM ET (US) aja your engine has the OIS optical ignition, have that checked. Klausds...yours does not have the OIS or I would mentioned that first.
aja	posted 09-22-2011 05:57 PM ET (US) With regards to ignition, I went on a wild ghost chase maybe 5 years back which started with replacing the power packs on the engine and went through all sorts of other things before completely rebuilding the carburetors which solved that problem. With that in mind I am more suspect of the fuel and/or carburetors now but suspect it is worth a check to be sure.
adlert	posted 09-22-2011 06:34 PM ET (US) Yes aja, checking an ignition system is always worthwhile. It's just so damned easy to do, and so absolutely necessary to have working correctly. Whenever approaching an engine running quality problem of almost any type, it is worthwhile first spending a few minutes checking spark presence/quality and also compression. Once done you can really start to home in on your problem and make good decisions regarding how much money and time your willing to pour into the repair effort.