Fuel Primer Bulb Goes Flat

[MrMckee]

I suspected I might have a bad primer bulb so I went to West marine and bought a new one. The new bulb goes flat after I run the motor on idle for 5 minutes but does not stall. It probably would with a load. My fuel filter only has maybe 15 hours on it. I took the line off of the motor and the line off of the tank and I can blow the gas through the line, filter, and into the can I had the hose in so no clogs there?? I took the connections off of the tank itself. The check valve in the piece that is barbed and gets connected to the hose seems ok, and the screen in the other part was clean??? If my vent is clogged I should be able to take the cap off the fill to see if the bulb inflates? If it does not can I take the spring and ball out of the barbed piece and it still function ok?? My boat is a 17foot Mckee Craft with a 1988 110HP Johnson. Any input would be greatly appreciated. Thanks.

 

[Silvertip]

Re: Fuel Primer Bulb Goes Flat

The restrictioin is between the primer bulb and the tank. Vent must be open. If there is an anti-siphon valve, it must either be removed or freed up. If the pickup in the tank is clogged it must be cleaned. The primer bulb has an arrow on it. Make sure it points toward the engine. The primer bulb may have a valve thats stuck shut. If this is a plastic tank, inspect the tank for plastic debris from the drilling operations. I've seen this stuff plug up a pickup and I've even seen pieces in the primer bulb. I have a habit of looking into brand new six gallon tanks at stores that sell these tanks and several have had a bunch of debris in them.

 

[Barnacle_Bill]

Re: Fuel Primer Bulb Goes Flat

That is a sign of a clogged vent. If you take the spring and ball out of the bulb, you won't be able to prime the motor properly.

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

Ok if it is a clogged vent I should be able to unscrew the gas cap and that would be a tell tale sign of a clogged vent. If that doesn't do it I am suspecting a defective primer bulb. I have an aluminnum tank built into the boat 32 gallons. The tank is only 3-4 years old. I know that doesn't matter. Thanks.

 

[Silvertip]

Re: Fuel Primer Bulb Goes Flat

You have an anti-siphon valve in the fitting at the tank. Not unusual for these to plug up or stick. Connect the hose to a portable tank and try it. Isolate the problem to the hose and bulb or the anti-siphon valve or pickup.

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

Yes I took that piece apart and it seemed to be working fine, no restrictions. The other fitting that screws down into the tank I took that out also to check the screen, it was also clean??

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

Well it is not the vent. I am going to replace the anti-siphon valve at the tank and check to make sure there is no obstructions in the pick up tube.

 

[Silvertip]

Re: Fuel Primer Bulb Goes Flat

It's also not uncommon for a brand new bulb to have a sticky valve.

 

[tashasdaddy]

Re: Fuel Primer Bulb Goes Flat

again the arrow on the bulb points toward the engine.

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

Yes just because it is new does not mean it could not be defective. When I was out in the boat and the bulb went flat I took it off and ran with no bulb, it still acted as ifit was starving for fuel. I got the anit-siphon valve, will put it on tomorrow. I plan on being on the water Saturday night. Thanks for your help.

 

[Water Plug]

Re: Fuel Primer Bulb Goes Flat

Hey MrMckee don't pull your hear out just yet.
Please take a look around for a kinked fuel line from the gas tank to the primer bulb.

Next remove the whole fuel outlet fitting from your gas tank the inlet might be partially blocked. If you have a fuel/water separator check on the flow path.

These suggestions are assuming you have checked your new bulb, anti-siphon valve.

Last ditch attempt is to remove all fuel lines and check for any obstructions in the lines.

Hope that helps you.
----
If you look for the complex,
you will always miss the simple

Brian~

 

[limacina]

Re: Fuel Primer Bulb Goes Flat

I bought a cheapo fuel bulb from walmart in a moment of despiration and it goes flat all the time. My other engine (twins) with the OMC bulb works fine.
I need to get out and purchase a decent bulb. I run 115 evinrudes and I think the cheaper bulbs don't have the volume.
Just another piece of onfo for you
AG

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

I took the new primer bulb back to West and they gave me a new one. I also installed a new anti-siphon- valve. Still bulb went flat. Before replacing new fuel line and fuel filter, that only has 15 hours on it, I took a piece of tubing 15(.') feet and connected directly to the anti- siphon valve then to new primer bulb then to another piece off tubing which emptied into a portable gas tank. I primed once, twice and bulb would not inflate. So belive it or not I must have something in the tank debri() that is partially clogging pick up tube. Like I said the tank is only 34- years old. My plan now is to get some small clear tubing and take off antisiphon- valve and elbo and stick down inthe tank and start priming or siphoning. Hopefull I can pick it up. I better I have no mor hair left to pull out. Thank you all foryour help!

 

[DJ]

Re: Fuel Primer Bulb Goes Flat

Just because fuel lines are new does not mean they are perfect. That issue has befuddled many a car/truck technician.

If the bulb goes flat, you have a restriction-PERIOD.

You are eluding to a bunch of crap, in the tank. The more I read, the more I think that is your problem. Satisfy yourself by borrowing a known good tank.

 

[tashasdaddy]

Re: Fuel Primer Bulb Goes Flat

you can put a new tank together at walmart for less than $ 20.00 tank and fitting. if that ain't it take it back. love the return policy.

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

There must be something in the tank but I have no idea how anything could have gtotten in there????:% I took out the antisipon- valve and elbow and I ran a small piece of clear tubing down the hole and attached the other end to the primer bulb. I pumped about a half gallon out thinking I could catch the crap when the bulb inhales, but I got nothing it pumped very well. When I attached the valve and elbow back the bulb will not inflate, also it makes a funny sound when trying to inflate like it is sucking air but that can not be or the bulb would inflate?? I replaced the antisipon- valve. On my old tank the elbow and the pick up tube were one piece, on my new tank the pick up tube is internal and the elbow screws down into the female threads on the tank. I am going to make some calls to see if I can find a one piece elbow and tube that will fit down in my tank. I will start with the fabrication shop that made my current tank. Any more suggestions for a hairless middle aged man??

 

[rickdb1boat]

Re: Fuel Primer Bulb Goes Flat

Just one. When you pump up the bulb, have the arrow end(the one going toward the motor) pointing up(Vertical). They pump up much better that way...

 

[Silvertip]

Re: Fuel Primer Bulb Goes Flat

Try positioning the primer bulb vertically (with the arrow up). Some of the bulbs don't like to function horizontally.

 

[MrMckee]

Re: Fuel Primer Bulb Goes Flat

I took a break from my tank today and ran through my head every possible scenario. This problem defies all logic. More food for thought, the boat runs fine when I have a full or 3/4 full tank, but once it hits 1/2 a tank that is when the bulb colapses. Does my pick up tube have a hair line crack?? I say no the bulb would still inflat with air, right??

 

[rickdb1boat]

Re: Fuel Primer Bulb Goes Flat

That certainly narrows it down to the tank. I'd look at the pickup real hard...