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Author Topic:   A Primer on Primer Bulbs
jimh posted 03-20-2002 01:29 PM ET (US)   Profile for jimh   Send Email to jimh  
Last season I overhauled the fuel lines on my 1987 Whaler. In the process I replaced the primer bulbs. I really have not been happy since then, until I discovered a secret that I am about to reveal to you.

But first, some history:

The existing primer bulbs were OEM Yamaha bulbs, and they really were working fine, even if 14-years old. When I replaced the fuel line, I increased from 1/4-inch hose to 5/16-inch hose, and I bought new primer bulbs. I got the TEMPO brand primer bulbs off the shelf at WEST Marine.

(By the way, I noticed a vast difference in the suppleness of the rubber in the dozen or so TEMPO brand bulbs hanging on the shelf. Some were very firm, some were very soft.)

When I put everything back together, I made the mistake of not pre-filling the fuel filter bowl of the water-separating filter with fuel. I had to squeeze a million times to prime the system. Finally I got gas through the hose, but the primer bulb behavior was qwerky. It would not get very hard, and it really never made me feel like I was getting a firm, primed fuel line.

The engines ran and everything worked well, so I just ignored it. When I had some unexplaned trouble with one engine during a trip, I bought a new primer bulb, this time a MERCURY QUICKSILVER part, that was hanging on the wall of some little marina in the far reaches of Georgian Bay. This did not seem to work any better, even though it cost me about three times what it would have in the States. To top it off, this bulb was stiff as hell, probably from sitting in that bubble pack for ten years on the wall of the marina before someone as crazy as me paid the asking price.

I complained to my Mercury mechanic, and he said try the newest Mercury primer bulbs. These are much improved, he claimed. So I bought another one and tried it.

The results were the same. The primer never got very firm, but the engine ran fine.

This spring, I was over at the shop checking on the boat (which is having some work done on the engine lower units) and complained to the mechanic about those primer bulbs. Then he showed me the problem.

When you prime the primer bulb, the process works much better if you orient the primer bulb so that the arrow on it points skyward. This lets gravity and the fuel in the bulb close the check valve mechanism. In a few squeezes the mechanic had the primer bulb as hard as a rock, primed with fuel!

Of course, once the magician reveals the trick, it makes perfect sense.

When I re-rigged the fuel lines, I had inadvertently changed the location of the primer bulbs so that the orientation of the arrow in the bulbs pointed downward. This tended to make the check valve not work as well, and the result was I could seldom (if ever) squeeze them to a nice firm primed state.

Those days are now over. I just have to move the primer bulbs to a section of the fuel line where they will point upward.

Am I the last boater on earth to discover this trick? I've never seen it mentioned anywhere.


Arch Autenreith posted 03-20-2002 02:32 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
I had it next to the fuel tank for awhile (pointing down). Then I moved it to just before the engine quick-disconnect (pointing up). I wasn't aware of any difference. I know, Jimh, you knew the arrow meant fuel flow. I can't imagine how in the world pointing it upwards would make any difference.
Soho posted 03-20-2002 02:34 PM ET (US)     Profile for Soho  Send Email to Soho     

Great pointer. I am just about to rerig my whole boat - new fuel lines and primer bulb etc included and your advice makes sense, in terms of the orientation of the arrow being upwards.



Bigshot posted 03-20-2002 02:54 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I have noticed though that the earlier gas lines had the primer less than a foot from the engine fitting causing it to face "skywards". The newer ones have it in the middle so i can see where that could happen (makes it easier to prime with foot though).

I also think the aftermarket primers are junk compared to OEM. In the old days they either got so hard you could not squeeze them or dry rooted. Today they just collapse...what gives.

jimh posted 03-20-2002 05:53 PM ET (US)     Profile for jimh  Send Email to jimh     
The point I was making is that the primer bulb works much better if you allow gravity to help the check valve operate. By pointing the arrow skyward you really increase the effect of the check valve.

I think the reduced fuel flow in some of these modern outboard engines has caused the makers of the primer bulbs to have to use a check valve that has less "spring" (for lack of a better term) in it, that is, it does not close off the reverse fuel flow path as strongly as check valves of old did.

My guess is that the slower fuel consumption rate requires a more sensitive check valve to prevent the check valve from affecting the forward fuel flow.


lhg posted 03-20-2002 06:21 PM ET (US)     Profile for lhg    
Jim: Are you sure you don't have bad anti-siphon valves at the tank withdrawls? I think I have this problem in my 18, assuming that one was factory installed (which I can not yet confirm). Evidently these things are notorious for fuel flow problems.

But I did have a primer bulb go bad on the 25, after about 8 years of use. You'll know it when it happens, and the engine will continually die out.

My Mercury engine manuals also talk about anti-siphon valves. They say the way to find out if you've got a problem is to run the engine (or prime the engine) on a separtate portable tank, and see if the problems disappear. This is my case.

I have never heard of this "upward arrow" configuration. On the 18, both of my primer bulbs rest horizontally on top of the starboard bracket, and work fine.

David Ratusnik posted 03-20-2002 07:07 PM ET (US)     Profile for David Ratusnik  Send Email to David Ratusnik     
Quality mechanics are trained to put the arrow up (skyward)--points toward the stern. Problem is--these bulbs degrade over several years. New, they work arrow toward the ground. Efficiency issue from what I am told. Been there. Curious re the upgrade to 5/16 fuel line?? Why? jimh- I am interested in your mechanic's or your own) stream of logic on the increase in fuel line diameter. Thanks David
triblet posted 03-21-2002 03:00 AM ET (US)     Profile for triblet  Send Email to triblet     
Pointing the bulb up is good BUT:

I don't think it's gravity helping the check valves, I think it's the getting the air out of the bulb and off down the line. Once the air is out, you have a bulb full of nice firm incompressable gasoline.


Clark Roberts posted 03-21-2002 07:05 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Thanks, Jim, I'm going to reorient all my primer bulbs as you describe! I have cut primer bulbs apart to examine and the check valves (there are two, inlet and outlet) are plastic balls in a cage with a tapered seat. I can see how orientation with arrow up will help the balls stay seated... great tip!!! Happy Whalin'...Clark .. Spruce Creek Navy
bdb posted 03-21-2002 07:24 AM ET (US)     Profile for bdb  Send Email to bdb     

After a lifetime of priming bulbs I spotted the same trick last summer. On the current Montauk, with a new oem OMC fuel line/bulb, I was never able to firm the bulb. The bulb is a short distance from the tank fitting, and thus points down to enter the tunnel.

While working on a persistent cold starting problem, the mechanic reached for the bulb, twisted it arrow-up, pumped a couple-a times and presto! Not only a firm bulb, but insta-start! I asked about his technique and his response was esssentially "what, are you a dummy?"

In hindsight any other rig I owned was either older (ancient design) or oriented arrow-up.

Who'd a thunk?

Harpoon Harry, aimed for the sky

Bigshot posted 03-21-2002 10:37 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Jim I was just bustin....

Guys new technology on primer bulbs......get an EFI and never touch that bulb again.

LarrySherman posted 03-21-2002 12:09 PM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
I replaced my fuel system last year as well, and had the exact experience Jim had. If I held the buld in a horiziontal orientation, I could prime for hours. If I move it to a vertical orientation, 3 pumps and she's (or IT, for the PC), done.

PS: OMC bulb.


Arch Autenreith posted 03-21-2002 12:41 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
A thought. Just because it doesn't get as hard as a rock when priming does that necessarily mean it isn't doing what it's supposed to do?

I can understand that the check valves will stay in a closed or 'anti-syphon' position if in the up position, but if not, as soon as you start to pump they'd close anyhow. So I guess you would get it to squeeze a little at first but by the end of the squeeze the results would be the same.

(I must be ready to go boating again if I'm thinking of a primer bulb this much.)

Salmon Tub posted 03-21-2002 05:56 PM ET (US)     Profile for Salmon Tub  Send Email to Salmon Tub     
Hey Arch, regarding that second to last message, if the outboard is a she and not an it, it may very well be important, to her anyway.
Salmon Tub posted 03-21-2002 06:00 PM ET (US)     Profile for Salmon Tub  Send Email to Salmon Tub     
Seriously, I had the cold start problem as well, but that was when I leaned out the mixture in my carbs, ran great once warm but would die 2-3 times when cold. The solution was to give it just a bit of gas at start up. I run my carbs dry at washdown so it takes me 7 or more pumps to prime the system.
fireball posted 03-21-2002 11:05 PM ET (US)     Profile for fireball  Send Email to fireball     
If the fuel pump is not developing 7-10 psi for the v-6's and v-8's the primer bulb is insignificant. Much of the fuel problems are due to fuel pump degradation. Use of a 1/4" fuel line supply would theoretically cavitate fuel needs of a v-6 at top rpm. fb flkeys
Arch Autenreith posted 03-22-2002 12:00 AM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     

I saw there were unintentual innuendoes but couldn't seem to edit them out. Oh well.

jimh posted 03-22-2002 07:59 AM ET (US)     Profile for jimh  Send Email to jimh     
Where in the fuel system should the primer bulb be located for best results? As close to the engine as possible? As close to the tank as possible? As midway as possible?
jimh posted 03-22-2002 08:15 AM ET (US)     Profile for jimh  Send Email to jimh     
Regarding the change from 1/4-inch to 5/16-inch lines: in my case I think that came about as the only solution I could manage from the parts IN-STOCK at the store that day. I bought new connectors for the engine end of the line, and I think they only had ones with 5/16-inch barbs. That set the size for the line, etc.

I also figured there was no harm in going to the large line, as mentioned by fireball the smaller line might be a problem with larger (more fuel thirsty) engines.

Whalerdan posted 03-22-2002 08:46 AM ET (US)     Profile for Whalerdan  Send Email to Whalerdan     
Jim - That reminds me of a saying my dad use to use all the time "If a little will do a little good, then alot will do alot of good".
Bigshot posted 03-22-2002 11:05 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I remember people saying oil is cheaper than metal when I was younger. They would mix 35-40:1 instead of 50:1. Could not figure out why the engine only lasted 4 or 5 years. Sometimes(with carbon) a little will do a little bad, a lot will do an engine in:)
where2 posted 03-22-2002 01:36 PM ET (US)     Profile for where2  Send Email to where2     
The big difference in pointing the arrows up or down is the ability to purge air from the primer bulb. Pointing down, if you have air in the primber bulb, you will likely force some past the inlet check valve back toward the tank when squeezing the primer bulb. Pointing up, you'll quickly purge the air by forcing it down the line toward the engine. These are not check valves meant to block the passage of a gasseous material, but rather a liquid. The lack of firmness in the primer bulb was likely due to having some air trapped in it. Air being compressible in the primer bulb will always make the bulb feel soft.
Dick posted 03-22-2002 03:59 PM ET (US)     Profile for Dick  Send Email to Dick     
My thoughts on the subject.
1: Tempo primer bulbs are junk.
2: the only aftermarket primer bulb I would use is a Sierra (Shields Hose).
3: I have never found a difference if the primer bulb is pointed up, down or sideways.
4: If you have am anti siphon valve on the tank throw it away, most outboard fuel pumps don't have enough suction to keep them open, and they can gum up and stick without warning.
5: The best location for the primer bulb is as close to the motor as possible.
6: Use at least 5/16 fuel line, nothing wrong with 3/8. The engine will only use the fuel it needs, the larger fuel line just supplys more fuel with less resitance to the point where it is needed.
7: Make sure there are no air leaks in the fuel delivery system between the tank and the engine.
jimh posted 03-22-2002 04:14 PM ET (US)     Profile for jimh  Send Email to jimh     
OK, one vote for "as close to engine as possible."

Any other opinions on the best location for the primer bulb?

lhg posted 03-22-2002 05:12 PM ET (US)     Profile for lhg    
All of Mercury's factory set up fuel line packages have the primer bulb about 18" from the engine end. Mercury uses 5/16" line, all size engines. OMC always used 3/8 hose.

I re-did both of mine with the Tempo 3/8" hose and primer bulbs, and after 5 years, still have no problems with the equipment.
My prior hoses were not alcohol resistant.

Tempo's lines put the bulb at the tank end, and I changed that configuration to stay with Mercury's recommendation.

jimh posted 03-23-2002 11:53 PM ET (US)     Profile for jimh  Send Email to jimh     
I was out cruising through two boat dealerships today (Saturday), and I noticed practically all the pre-rigged engines on new boats were set up with the primer bulb about 18-inches from the engine.

It sounds like that is the right place for them.

TightPenny posted 03-24-2002 01:50 PM ET (US)     Profile for TightPenny  Send Email to TightPenny     
Watch the Tempo bulbs. If you step on them and weigh as much as I do, you can dislodge the check valves inside of the bulb. When they float around inside of the bulb they will float into the discharge side of the bulb and block fuel flow. This makes for an real interesting intermittent fuel starvation problem, mostly at higher RPM's.
David Ratusnik posted 03-24-2002 07:57 PM ET (US)     Profile for David Ratusnik  Send Email to David Ratusnik     
Well I played with my primer bulb Sat and Sunday. Total cold start Saturday, I twisted it 90 degrees so the arrow was horizontal to the water. Squeezed it 3 times- didn't get hard. Soooo, let it settle back to where the arrow was straight up (arrow toward the engine-obviously), squeezed 3 more times and it hardened. I know, not a conclusive test! Went to the console, twisted and choked (depressed) the key and bang- started right up. The primer bulb is about 18" from the engine as per jimh. The bulb is OMC less than 6 months old. Enjoy. David
Bigshot posted 03-25-2002 10:06 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
With fuel injection....don't need one.

But.....mine is about 18-24" from engine pointing skyward.

Chap posted 03-25-2002 10:34 AM ET (US)     Profile for Chap  Send Email to Chap     
My bulbs are about 18" from the water separators on the tank side, factory installed. I took a look at my OMC manual for my 1989 120 Johnsons and it says for both the oil and fuel line to tilt it up before squeezing, very casually I might add. Of course no squeezing the oil if already primed or you think you have an air pocket burp because you neglected to keep you oil tank full.
ShrimpBurrito posted 06-17-2002 04:32 PM ET (US)     Profile for ShrimpBurrito  Send Email to ShrimpBurrito     
I started having problems with the new primer bulbs I installed on my '86 40HP Johnson, so, I removed them. Straight fuel line from tank to engine. The engine still starts cold within 2-3 tries, max.
Highwater posted 07-01-2002 10:29 PM ET (US)     Profile for Highwater    
Larry and Dick's comments about anti-siphon valves going bad have me thinking that this may be the reason the 70 hp Nissan on my 15' runs rough at mid-range speed (and why I keep getting air in my line). But I don't even know what an anti-siphon valve looks like to know if I have one. If I start unscrewing hardware from my tank will I find it? Can I run over to West Marine and replace it? Thanks! David.
jstachowiak posted 07-03-2002 08:58 AM ET (US)     Profile for jstachowiak  Send Email to jstachowiak     
Just ruined a family trip to the beach here in St. Augustine because my 90HP 1979 Mercury would not start after 30 minutes of cranking until the battery died. There was never a pop, smoke or smell of gas during this time. I thought the carbs needed work, but mechanic said my new Tempo primer bulb may be the culprit, since when he started the motor it started right up. He is replacing the Tempo bulb with the new Mercury bulb with a yellow band on it. He said Merc has stated to look for the yellow band on the primer bulb and if it doesn't have that band to replace it.

I tried the "pointing the arrow skyward" trick but that did not work for me.

I'll be curious to get it back next week (having water pump impeller replaced) and see how it starts.

DanT posted 07-03-2002 09:09 AM ET (US)     Profile for DanT  Send Email to DanT     
I installed a couple of clear inline filters between the primer bulbs and the engine on both of the fuel lines. Besides catching any particulate before it gets to the engine it makes it easy to see if there is fuel flow.
Highwater posted 07-03-2002 08:20 PM ET (US)     Profile for Highwater    

If you are going to use the Tempo inline fuel filters, you might want to carry a spare. The glass can break, as can the little gray threaded piece inside. And unless you use Teflon tape, they can sometimes let air into the line.

Just an idea....


Jay A posted 07-05-2002 12:06 PM ET (US)     Profile for Jay A    
This is my second season with my "big boat" and I have yet to prime the bulb! I have a 200hp Suzuki and the dealer said I shouldn't have to as long as you have fuel. 81 gallons of fuel capacity probably has something to do with it,I haven't run dry yet!
jstachowiak posted 07-05-2002 10:03 PM ET (US)     Profile for jstachowiak  Send Email to jstachowiak     
Lurking on and seems everyone there installs an automotive electric fuel pump at the fuel tank. Anyone here done that?
acseatsri posted 07-05-2002 10:13 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
Both the clear filters on the fuel lines and the electric fuel pumps seem dangerous. I'd stick with the sidewall-mounted filters and use the fuel pump that came installed on the engine. Never had a problem with either before. If you have a leak with an electric fuel pump, you could have some serious gasoline in the boat before you knew what happened. Same with the clear plastic inline, especially sitting out in the sun.
WantaWhale posted 07-16-2002 12:15 AM ET (US)     Profile for WantaWhale  Send Email to WantaWhale     
I broke down last year in part because of an old primer bulb. Boat would get on a plane then run out of gas and bulb would lose pressure. I replaced the bulb and one of the connectors and had the same problem. I had bought 2 of everything so I tried the second set. Still the same problem so I started thinking something else was wrong. I called my mechanic and he asked me what I bought. He stopped me there and told me the problem was the Tempo brand . Said they had about 60-70% failure rate right out of the box. I still didn't see how 2 brand new sets could be bad but sure enough, as soon as I replaced with OEM the problem was gone. The thing is , the tempo actually looked better built (heavy duty). Another thing about tempo, I bought a small 3 gallon tank for backup. Brand new the thing leaks. Most of the stuff I get from Boat us and West are top notch, but I would not recommend tempo.
lhg posted 07-16-2002 02:55 PM ET (US)     Profile for lhg    
I have leak experience with Tempo tanks also.
But I have found that resealing ALL of the threaded connections, including brass-to-plastic and plastic-to-plastic, with teflon tape does the trick. Also, don't let pressure build up in the tank, and open the vent screw just a little.
frank_king posted 04-19-2003 02:45 PM ET (US)     Profile for frank_king  Send Email to frank_king     
tempo is junk, in my first hand dealings with the product. i wouldn't buy there fuel tanks, there fuel line, or there fuel bulbs. they are worried about selling product.

mercury and omc what you to have quality products that will keep you on the water, not wanting to be on the water with an engine that will not start or perform because of a bad fuel system.

nothing replaces mercury or omc parts.

lhg posted 06-17-2003 06:11 PM ET (US)     Profile for lhg    
I have to join the chorus of those who think Tempo brand primer bulbs are no good!

In 1997, on my 18 Outrage with twin in-line Mercury 6's, I replaced the original fuel lines & primer bulbs (by Mercury) since they were not the alcohol resistant type. I used the then current Tempo products, 3/8" size. Shortly after, without realizing it, I began having fuel starvation problems with both engines when accelerating. My Dealer said it was alcohol in the fuel, and I should set the low speed jets for a richer mixture. To get the engines to accelerate properly, I had to set them VERY rich, but still had the stall-out problems intermitently, over the last 6 years. I had the engines looked at many times, complaining of this problem, but the dealership insisted they were perfect. They always plugged in their shop fuel supply, and never mentioned that the fuel supply in the boat could be bad!

Well, after thoroughly reading my engine manual, vapor lock kept showing up as a cause of the condition. I had already looked into the anti-siphon valve situation, and found my Whalers did not have them at all at the tank withdrawl.

One day a few weeks ago, while shopping at Walmart, I noticed Attwood brand primer bulbs for $5. This was the only element in my fuel withdrawl system I had not changed. So I replaced the Tempo bulbs, and PRESTO, the engines run better than they have in 6 years, with no fuel starvation/vapor lock at all.

My recommendation would be that if you have one of these Tempo primer bulbs in your system, GET RID OF IT! I have generally had good results from Tempo products, including their tanks, but the primer bulbs I had were a disaster, and they looked perfectly new on the outside, with none of the priming problems mentioned in this thread. I guess the anti-siphon valves in them are no good.

message posted 6-17-03

Dick posted 06-18-2003 12:21 AM ET (US)     Profile for Dick  Send Email to Dick     
Having been in both the wholesale and retail side of this business I have never had a problem with any Tempo product and few with Attwood. If in doubt go for the OEM brand.


lhg posted 06-18-2003 10:00 AM ET (US)     Profile for lhg    
Dick - I'm confused. See your message posted above 3-22-02.
BQUICK posted 06-18-2003 04:42 PM ET (US)     Profile for BQUICK  Send Email to BQUICK     
I just replaced a new Tempo primer bulb on my Allison with a Quicksilver (yellow band) and now it starts MUCH quicker cold. Worked for me.
jimh posted 09-30-2003 09:38 PM ET (US)     Profile for jimh  Send Email to jimh     
[Removed some diversionary discussion from the thread--jimh.]
doncarlos42000 posted 05-24-2008 07:28 PM ET (US)     Profile for doncarlos42000  Send Email to doncarlos42000     
I have a 1991 Johnson 15-HP (on a 14-foot Jon Boat), and after a tune up the motor still would cut out and its idle was rough. I cleaned the carburetor and the motor ran great, but the motor would still would die out after eight seconds of full throttle. I notice my [fuel line primer bulb] was always soft and empty when this happened. After reading this article, I looked and [the flow direction arrow on] my [fuel line primer bulb] was pointing down. I flipped it up and WOW, I had to adjust the lean-rich and now [the motor] really flies. Thanks for all the advice. My fuel line and [primer bulb] are the Atwood brand (and cost $19.00). I have never had a problem with any of their products. Of course nothing beats OEM parts and equipment. If you got it get it, nothing is worse than buying something twice. Thanks for the advice.
jimh posted 05-25-2008 08:22 AM ET (US)     Profile for jimh  Send Email to jimh     
Also see the REFERENCE section for this article:

A Primer on Primers

seabob4 posted 05-25-2008 02:11 PM ET (US)     Profile for seabob4  Send Email to seabob4     
Believe it or not, we use OMC(BRP) primer bulbs on all engine models, Suzuki, Merc, BRP, and Honda. Would DEFINITELY use it on Yamahas too if we did them. I have always found that the OMC primer bulb was the stoutest, most well made of them all. And of course, have the arrow pointing up. Just my 2 cents...
chopbuster posted 05-30-2008 12:57 AM ET (US)     Profile for chopbuster  Send Email to chopbuster     
I've not had to use the primer bulb whatsoever on my 150 Sport/EFI 60hp Bigfoot, before or after fill-ups.
jimh posted 05-30-2008 08:53 AM ET (US)     Profile for jimh  Send Email to jimh     
Fuel systems with fuel-injection do not tend to lose prime due to fuel evaporation. They also tend to have electric fuel pumps which operate without being completely primed. Older outboards use a engine vacuum fuel lift pump.
Ronron posted 06-04-2008 02:09 PM ET (US)     Profile for Ronron  Send Email to Ronron     
Thanks Jimh for your info on gas priming bulbs. Pointing bulb up solved my problem. I had taken the bulb off the tank, blew into the valve in both directions and was surprised at how it seemed to stick at times. Pointing the arrow upward must help the valve seat properly. (and some are probably poor quality) Thanks agaain.
Ridge Runner posted 06-05-2008 04:55 PM ET (US)     Profile for Ridge Runner  Send Email to Ridge Runner     
I added a Yamaha 10 micron filter to each of my twin 02' Optimax fuel systems; I also had to replace the hoses to the primer bulb as I needed more length, while in the process I figured I should change the primer bulbs. My original Merc’s would get your hand all black and filthy. I choose the Tempo ultimate flow bulbs, when running at 3/4 throttle my starboard engine would shut down. This drove me nuts trying to figure out, so much discussion on the Opti's and don’t put a second filter in line because the fuel pumps aren’t strong enough..well after taking the Yamaha filter out of the fuel delivery line I still had the same problem, and I had this nagging issue of the bulb being soft, so I changed out the bulb to a QuickSilver one and presto the problem stopped, put the Yamaha filter back inline and everything works great. I opened up the Tempo bulb and you can see how the check valve ball can cause flow restrictions.
Chinook1 posted 07-26-2010 11:47 PM ET (US)     Profile for Chinook1  Send Email to Chinook1     
[A vulgar expression of surprise had been deleted] This discussion has been my Summer [dealing with problems on a] 2006 very-well-cared-for Mercury [outboard] with low hours. [As preventative maintenance] a tune up was done this Spring in which all the fuel lines and primer were replaced. [The Mercury engine has been] having on-and-off power problems all Summer, which came to full force this weekend. The fuel filter was changed to a see-thru fuel filter, and it was discovered the engine was getting no fuel. On a whim the fuel line and primer bulb were changed--luckily [to something other than] a Tempo--and the problem was solved. This discussion was read afterwards; lo and behold in the garbage was a Tempo primer.
sternorama posted 07-27-2010 12:26 PM ET (US)     Profile for sternorama  Send Email to sternorama     
In the intended vertical orientation, the fuel head within the bulb--the volume of fuel in the bulb affected by gravity--helps to seat the check valve element, resulting in a firm bulb due to reduced leakage at the valve seat. Cheers!
Chuck Tribolet posted 07-27-2010 04:50 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The vertical orientation also causes the bulb to pump the
air out, which results in a bulb full of fuel.


thegage posted 07-28-2010 08:59 AM ET (US)     Profile for thegage  Send Email to thegage     
The Operator's Guide for my 2010 E-TEC 30 states, "Squeeze fuel primer bulb, outlet end up, until firm."

Guess it's not that big a secret.

John K.

jimh posted 07-28-2010 07:57 PM ET (US)     Profile for jimh  Send Email to jimh     
I guess word has gotten around in the eight years since I began this discussion with the observation about orienting the primer bulb upwards.
John McBride posted 08-01-2010 12:00 PM ET (US)     Profile for John McBride  Send Email to John McBride     
I had to figure this one out on my own. My Olson 30 came with no outboard. I bought a Nissan 4s 6 hp and it worked like a champ for a while and then I couldn't get a firm bulb as well. I heard the check ball rattling as well and thought gravity might help and tried what you describe. BINGO
Seminole Jack posted 08-02-2010 10:52 PM ET (US)     Profile for Seminole Jack  Send Email to Seminole Jack     
[This is a fellow who goes by "Binky" who has been banned. He wrote a silly article which said he invented this technique in 1958. His article was intended to ridicule this discussion. This sort of contribution is part of the reason why his user is no longer welcome to particate here.--jimh]
wilbglc posted 09-02-2010 11:19 AM ET (US)     Profile for wilbglc  Send Email to wilbglc     
One thing I think I need to clear up on this entire discussion. It seems that the solution being described here requires the outlet of the primer bulb, NOT THE ARROW, need to be pointing upward.(obviously if you hold the bulb vertically, the arrow's point will also be pointing upward). The confusion I seem to be observing is some people think the arrow pointing up is the solution. Clarification: The arrow can be at the topside of the bulb(therefore the arrow being situated skyward) with the bulb still being in a horizontal position. This will not help a primer bulb problem. We need to KISS (keep it simple stupid) and simply state to position the bulb vertically...period. The only purpose of the arrow is to orient the direction of the fuel flow. As long as the arrow is at the engine side of the bulb you are all set. Hope this helps.
jimh posted 09-06-2010 01:14 PM ET (US)     Profile for jimh  Send Email to jimh     
Thanks for the clarification, but I do not think it was necessary. I do not think anyone was confused about the orientation of the arrow as compared to the orientation of the primer bulb inasmuch as the two are always aligned owing to the arrangement of the arrow being molded on the primer bulb.
skimywhistler posted 06-24-2012 02:04 PM ET (US)     Profile for skimywhistler  Send Email to skimywhistler     
I see some people have said get [EFI] or fuel injection and you won't have [the problem of the primer bulb not getting firm]--rubbish! I have had a problem with not getting air out of the bulb. I have a fairly new motor with original fuel line and bulb. I noticed getting the bulb filled with [fuel] was a real [aggravation]. My old Evinrude 25 never had this problem with filling the bulb. The bulb was closer to the engine which meant it was usually pointed up. My newer Evinrude [E-TEC] has the bulb closer to the tank. Guess what was happening? The arrow was usually down. Just like a previous person mentioned, in the Evinrude manual [there are insturctions to orient the primer] bulb [upward]. To bad I did not notice this when I read the manual!!!
jimh posted 06-24-2012 05:10 PM ET (US)     Profile for jimh  Send Email to jimh     
...I have had a problem with air not getting out of the bulb. I have a fairly new motor with original fuel line and bulb. I noticed getting the bulb filled with [fuel] was a real [aggravation]. My old Evinrude 25 never had problems with filling the bulb. The bulb was closer to the engine which meant it was usually pointed up.

I don't think the engine type affects the operation of the check valves in the primer bulb. Orienting the bulb so its arrow points skyward helps the operation, no matter what type of engine is being fed by the fuel hose.

My newer Evinrude [E-TEC] has the bulb closer to the tank. Guess what was happening? The arrow was usually down. Just like a previous person mentioned, in the Evinrude manual [there are instructions to orient the primer] bulb [upward]. Too bad I did not notice this when I read the manual.

Based on your recitation of the E-TEC operating instructions, it appears they agree with the recommendation I made in my article from 2002, and with the experience of almost all the participants in the discussion. Those Evinrude folks are sharp operating manual writers.

Also, Evinrude typically does not rig the fuel line in a customer's boat. The customer or the dealer do that. So Evinrude does not really have any control of how the fuel primer bulb ends up being located or oriented on a boat. That is up the the dealer or the customer.

LakeArrowEd posted 06-10-2014 12:40 AM ET (US)     Profile for LakeArrowEd  Send Email to LakeArrowEd     
I just threw away a barely used one year Tempo fuel line with primer bulb. What a piece of junk. The 1983 Johnson J35ELCTS on my 1977 Super Sport 13 started acting up the other day. From WOT it would die down to an idle and when I throttled back for a little bit then nailed it, it would go for a little and do the same thing again. I immediately suspected fuel starvation and could picture that bowl refilling at idle and then emptying when I throttled up. I did a quick search of CW and BINGO saw the repeated post about Tempo fuel lines. Luckily the guy I originally bought my Whaler from had a ton of extras that came with it which included four brand new, still-in-original-packaging, OEM, early-2000's OMC fuel lines. So before going bonkers and tearing the carb down and any other suspect part, I simply hooked a new OMC fuel line up and--BANG--what a difference a fuel line makes. My son and I went screaming around the whole lake without so much as a hiccup. Man I love this thing when it runs right! My take is the Tempo lines are garbage.
gr4474 posted 07-29-2014 12:25 AM ET (US)     Profile for gr4474  Send Email to gr4474     
I bought a bulb kit from Bass Pro Shops, that has the gray hose attached. My engine kept cutting out, as if it wasn't getting gas, so I replaced the bulb, but kept the hose. Same problem. Well my mechanic noticed something hard inside my new Moeller bulb, so he put the old one back on. He also noticed that there is a plastic liner in the fuel line, that had ate away and collapsed, and causing the problem. When I put the new bulb in, the gas was getting on the OUTSIDE of the liner. So after replacing the fuel line, they noticed that the clamps on the original bulb were leaking air, and what caused my problem in the first place. It's the clamps that tighten the bulb onto the nylon barbs on each end. They said this is common, and they just put zip ties next to the clamps to get a good seal. Screw clamps would also work. Worked like a charm! Running great all week.
jimh posted 07-29-2014 07:09 AM ET (US)     Profile for jimh  Send Email to jimh     
Avoid that gray fuel line like the plague. It can't tolerate ethanol-gasoline blended fuels.

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