Fuel Tank Pickup Problem

Our GT150 seems to "run out of fuel" with about 8gals left in our 30gal tank. Which means there is about 5" of fuel left in the tank. The pickup is about 1" from the bottom of the tank to avoid sedament, I assume. I checked the vent for restriction, there is none. However, when I tested the anti-flow back valve in the fuel pickup it is very hard to blow through in the direction of the fuel flow. My question, shouldn't it flow fairly easy? My thought was that if it is too restrictive that as the fuel got lower in the tank, it'd be harder for the pump to pull it up the pickup and out of the tank, explaining the reason why we "run out of fuel" with nearly a quarter tank. Any opinions/input would be a help. Thanks.

Re: Fuel Tank Pickup Problem

It may be the Antisiphon valve. It also may be some debris clogging the fuel pickup tube. When the fuel is low, the debris can get concentrated. Certainly the easiest solution is to remove the A-S valve. If I were you, I would pull the fuel gauge sender and have a look at the fuel in the tank.

Re: Fuel Tank Pickup Problem

I was told by a local marine supplier/shop to just "knock the ball out because it restricts flow...". I suspect mine is restrictive but am afraid that if I do away with it I'll have to reprime the line every time I shut off my engine! Any advice from experience would be a huge help!

Re: Fuel Tank Pickup Problem

Thanks for the reply Chris1956, I pulled the tank 2weeks ago and cleaned it, and all lines and the vent, performing normal maintenance. The problem has existed before and since then. I did pull the pickup today and inspect the tank, both were spotless...
Have you or anyone else done away with the ball in the pickup fitting as was suggested by one of our local shops?

Re: Fuel Tank Pickup Problem

CadillacsCowgirl said:

Thanks for the reply Chris1956, I pulled the tank 2weeks ago and cleaned it, and all lines and the vent, performing normal maintenance. The problem has existed before and since then. I did pull the pickup today and inspect the tank, both were spotless...
Have you or anyone else done away with the ball in the pickup fitting as was suggested by one of our local shops?

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I had to on mine, you need to order a new pick up tube measure from the bottom up to the bottom of tank, and cut the new one at a 45 , There is a Coast Guard rule for Anti Syphon valves that you must read to make sure you can knock it out.It talkes about the Fuel Tank Position. Also make sure you have a fuel separator if you remove the screen in the tube.

Re: Fuel Tank Pickup Problem

Antisiphon valves are intended to stop the siphon action, if a fuel line were to break and the break was below the level of fuel in the tank. This often exists on I/O boats, but not ofter on OB boats. I have removed my A-S valve as I had a restriction at high RPM.

Re: Fuel Tank Pickup Problem

Thanks for the replies. I'll check the CG regs to verify I'm legal and then do away with the A/S valve then, it's worth a try to correct the issue. Luckily ours is actually made into the barb fitting that screws into the top of the pickup so it's as easy as purchasing a new barb fitting. Hopefully it'll allow us to use more than 75% of the fuel in our tank! Thanks again for the great input!

Re: Fuel Tank Pickup Problem

We are within the CG regs. It is that our tank and its fuel feed are below the level of the fuel line and engine preventing the flow of fuel in case of a break in the line or a failure in the engine fuel system...
Thanks again for the info!

Re: Fuel Tank Pickup Problem

Replaced the barb containing the A/S valve with a normal 3/8 barb, problem seems to be cured.