Is my gas tank feed plugged up?

[Jazzbari]

Yesterday I took my 2004 5.7 Volvo I/O out for a spin. I noticed it only made 3000 at WOT. Then it really started losing power and finally I was DIW. Oil pressure and temp were normal. Today every one was telling me it was water in the fuel because of the new E10 gas. Fuel pump runs when I power the ignition switch. I removed the fuel filter (no water separator) and noticed it was just 1/4 full and the fuel line hose was dry. Here come the 64$ question. Can one suck or blow into the disconnected fuel line with out feeling a restriction. I play baritone saxophone and with my lungs I can't get any air down that tube or gas out of it. Tank is 3/4 full. Right now I don't want to rig a separate hose and gas tank ( I'm leary of fumes) to see if the engine runs. I just want to know how I can tell if the fuel tank feed is clogged. Is it OK to shove a stiff wire into the 3/8 elbow at the top of the tank?

 

[Don S]

Re: Is my gas tank feed plugged up?

That fitting the hose hooks onto in the top of the tank is an antisiphon valve. That in itself means you can't blow thru it.
Sticking a wire in it would also be useless. It's an elbow, and below the elbow and going to the bottom of the tank is a stand pipe (Should be called a down pipe I guess) but anyway, the pipe sticks down in the tank about 3/8" off the bottom of the tank. So it pulls the gas out of the bottom of the tank, if it pulled from the top, you would run out of gas pretty quick.
If you suspect a plugged line or possibly an air leak, there is a way of testing for that.
Here is a thread I posted some time back that should explain it.
http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

Also, since you have a Volvo, it does have a fuel filter/water seperator on the engine.
If you would post the model number or better yet the Serial Number of your engine, I may be able to help you with some other info, but 04 5.7L Volvo I/O doesn't help much.

 

[Jazzbari]

Re: Is my gas tank feed plugged up?

That fitting the hose hooks onto in the top of the tank is an antisiphon valve. That in itself means you can't blow thru it.
Sticking a wire in it would also be useless. It's an elbow, and below the elbow and going to the bottom of the tank is a stand pipe (Should be called a down pipe I guess) but anyway, the pipe sticks down in the tank about 3/8" off the bottom of the tank. So it pulls the gas out of the bottom of the tank, if it pulled from the top, you would run out of gas pretty quick.
If you suspect a plugged line or possibly an air leak, there is a way of testing for that.
Here is a thread I posted some time back that should explain it.
http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

Also, since you have a Volvo, it does have a fuel filter/water seperator on the engine.
If you would post the model number or better yet the Serial Number of your engine, I may be able to help you with some other info, but 04 5.7L Volvo I/O doesn't help much.

 

[Jazzbari]

Re: Is my gas tank feed plugged up?

Don, That info link assumes that the engine is running so it won't tell me why the pump isn't drawing fuel. But now that I have learned where the anti-siphon valve is located and why I cant blow thru it, can it easily be removed to check for blockage? The elbow seems to just unscrew. And you are right in assuming that I may have a water separator, but i'm not sure from just looking at my fuel filter setup. The engine SN is 4012122675 (5.7 OSi-DF)

 

[DJ]

Re: Is my gas tank feed plugged up?

Yes, you can remove the anti siphon valve for testing.

 

[Jazzbari]

Re: Is my gas tank feed plugged up?

Gosh
don, this is the best site for boat maintenance info. A million thanks, Al

 

[Don S]

Re: Is my gas tank feed plugged up?

The tests I link you to will also work for your problem. With the OSi engine, when you turn the ign. switch to on the fuel pumps will run for about 2 seconds and shut off. If you watch the gauge and the clear fuel hose, you will see if air or fuel is moving, and if there is a plug you will see the vacuum build. You may have to try several times.
Or you could go right straight to removing the antisiphon valve and the pickup tube out of the tank. The pickup tube has a screen on the bottom that can get clogged. I would pull the boat out of the water and have it bow down so gas doesn't come out of the tank in case it's too full.
If you don't find any indication of clogging and your vacuum gauge doesn't show any vacuum building up, you may just have an air leak. Check the fuel lines from the tank to the engine for loose hose clamps.
After all that, and you find nothing, you really need to get the fuel pump pressures checked to see if the pumps are working properly. You have 2 pumps, a low pressure and a high pressure. If the low pressure pump or relay isn't working, the high pressure pump will run out of fuel like it did.