Fuel delivery issue

[kevinclark93]

Okay guys I wanted to get some thoughts on my fuel problem.

I took the boat out this weekend with all of the crazies 96 150 merc carbed. Ran great for about 15 minutes and then stalled recovered the stalled and died. I pumped up the primer bulb again to restart and when the bulb collapsed it took it awhile to recover. We finally got a few pumps of gas to the motor and it cranked up and we ran for about 10 seconds and died again. We where trying to pump the primer bulb while running but it took it a long time to recover after each pump, as in it stayed collapsed. Once it died we fought the bulb until we could get a little gas to the carbs and we could run for about 10 seconds and it would die again.

We repeated this process several times each time getting a little closer to the ramp. I finaly broke out the spare primer bulb I had on board and hooked it up bypassed the water separator just in case that was the problem. The boat fired up and ran fine after that. We probably ran about 20 minutes total and went back to the ramp. The next day I cranked it up in the boat slip and it was expiercencing a similar issue it would not idle. I also noticed that the primer bulb which is brand new now was vibrating. I have installed a new water seperator and finally got to a point where it will idle fine, but i have not taking it out again.

Should i rebuild the fule pump or is there something else i should look at?

 

[Chris1956]

Re: Fuel delivery issue

If the primer bulb collapses, there is a restriction between it and the fuel tank, or the fuel tank breather is clogged. Figure out which it is and fix it. The fuel pump will need to be rebuilt only if the engine starves for fuel and the primer bulb is not flat.

 

[kevinclark93]

Re: Fuel delivery issue

Is there a good way to test the tank breather? Also where is the tank normally vented to?

 

[sschefer]

Re: Fuel delivery issue

Is there a good way to test the tank breather? Also where is the tank normally vented to?

Kevin, do you have a below deck tank or above? In either case just open the filler cap and if it's a venting problem it will go away. If it's below deck then you have a shut off valve and it may be an anti-siphon style. These are notorious for sticking and causing the problem you describe. The other thing it might be is sludge in the pickup tube. You can use compressed air to try and clear it but without a good tank cleaning it will probably come back on you. Do the compressed air thing outside with plenty of ventalation and don't smoke.

 

[kevinclark93]

Re: Fuel delivery issue

Thanks for the input. I have a 50 gal below deck tank, I will try the compressed air, aslo how do you trouble shoot the anti-siphon or do you just replace that. I know my tank has junk in it, every time I change my water seperator I pour it into a clear jug. There is always some amount of trash in the gas.

If I wanted to clean my tank how would I do that?