fuel line syphoning behind primer bulb?

[jtcarter]

Well i have a 175 evinrude intruder. I was doing some trouble shooting. Seems to happen with this motor alot. I'am about to start comparing it to a harley. Anyway back to the subject. I don't have a antisyphon valve at the tank, i took it out. Brand new fuel line from tank to motor. I have a primer bulb and a see thru plastic inline filter on the fuel line. The filter is in front of the primer bulb. I start the motor and you can set there and watch it lose prime through the filter. If you take the hood off my motor at the fuel line connection is a see thru tube. You can set and watch air bubbles go past then it goes about half empty. I think the fuel tank is sucking the fuel back to the tank, syphoning it back. I was told i didn't need the antisyphon valve at the tank. What i'am i missing here. I know why my motor hasn't been running well but i don't know the root cause. I took the pickup tube completely out of the tank and leak tested it. Its fine. The vent is clear and the primer bulb and filter are in upright position for obvious reasons.This one has me stumped any help on the matter would be appreciated.

 

[Dhadley]

Re: fuel line syphoning behind primer bulb?

The bulb should have one way valves (some after market ones don't) which should stop any line loss. Also be very very careful with an inline glass filter on a V6. Can be a fuel restriction and be very costly.

 

[jtcarter]

Re: fuel line syphoning behind primer bulb?

The bulb should have one way valves (some after market ones don't) which should stop any line loss. Also be very very careful with an inline glass filter on a V6. Can be a fuel restriction and be very costly.

First bulb i had on there was a omc bulb from the dealer bought earlier this year. Tried a different aftermarket bulb and got same results. The filter is a plastic one not glass. Filter should stay full of fuel. I've even disconnected it and filled it full and it still sucks it down until it pulls air. Two different primer bulbs shouldn't be bad and i know the omc has one way valves. What gives?

 

[tashasdaddy]

Re: fuel line syphoning behind primer bulb?

check the vent on the fuel tank, the pick up tube in the fuel tank could be clogged.

 

[Dhadley]

Re: fuel line syphoning behind primer bulb?

The valves tend to work much better if the bulb is vertical so since you had it that way perhaps the solution is replacing the anti-siphon valve at the tank.

 

[jtcarter]

Re: fuel line syphoning behind primer bulb?

The valves tend to work much better if the bulb is vertical so since you had it that way perhaps the solution is replacing the anti-siphon valve at the tank.

Thats the only thing left i would think. Tashasdaddy i've checked both vent and pickup tube. Even took it out and leak tested it. Took the gas cap off to make sure my vent was big enough didn't affect anything. Gators, tebow(tebag),urban cryer. Go vols baby,lol Just joking with you. Lookng forward to seeing the gaytors in september at neyland

 

[jtcarter]

Re: fuel line syphoning behind primer bulb?

Ok what now? I get the antisyphon valve put it on. I set there watching the filter it pulls it dry again. I take off the inline all together and watch the little see thru plastic peice at my fuel connection at the motor i watch it for a minute or two it stays solid for a minute then sucks a bubble in ther then goes to about half full again. The antisyphon valve made no difference. This one is a stumper. I guess there could be a pin hole in my fuel line somewhere. But i doubt it since its brand new. Anybody got any idea what on earth this could be. Checked vent even took cap off to make sure, no difference. I've taken the pickup tube out filled it full of water and watched for any leaks,none. Even blew thru it and held pressure on the connection side, no air escaped. This just doesn't make much sense. Seems like a air leak but where? I suppose i could rig some kind of vaccum test to the line from the tank and cap it at the fuel pump end to make sure. Man i'am out of answers.

 

[CatTwentyTwo]

Re: fuel line syphoning behind primer bulb?

I like the J/E plastic ratchet style hose clamps. I think that they provide better 360 degree clamping than some of the stainless hose clamps. I also use pipe compound on the tank fittings. Good luck and I hope that you find your problem.

 

[jtcarter]

Re: fuel line syphoning behind primer bulb?

I like the J/E plastic ratchet style hose clamps. I think that they provide better 360 degree clamping than some of the stainless hose clamps. I also use pipe compound on the tank fittings. Good luck and I hope that you find your problem.

I found my problem. This is for anyone with a fuel delivery problem. Don't use zip ties on the vaccum side of your fuel line. I feel like such a dufus. I changed all of my clamps from zips to stainless steel earlier. Primed my little filter got all the air out. Now my fuel line is staying primed. I think i finally figured out my whole problem. A one dollar hose clamp. Man this has been some trying deal. Took it too i don't know how many mechanic's trying to figure out the lean sneeze deal. They all overlooked the obvious just as i did until now. Well problem fixed, if your think your having a heat soak problem or a fuel delivery problem make sure you have stainless steel clamps on the vaccum side of your fuel line or you'll be scratching your head just like i was.

 

[kenmyfam]

Re: fuel line syphoning behind primer bulb?

Glad it was that simple a fix once you found it.