engine will not run under a load with inboard gas tank

[86bayyliner]

i have a 1990 evinrude 150 on a 1986 bayliner and the bulb in the back collapses whenever its under a load. i changed the bulb and its not that.. there is some **** in the tank.. i put this stuff in the tank that breaks down the stuff in the tank and got a new water separator and it still doesn't work in the water... on land its fine.. i hook up an external gas tank and the boat runs fine.. the vents are all brand new and so is the hoses.. even when i bypass the water separator it does it/// please help.. i have tried almost everything besides ripping out the gas tank and not going to do that.. the tank is 97g galvanized aluminum tank,, thanks,,,

 

[rbh]

Re: engine will not run under a load with inboard gas tank

your breather line or pickup line is pluged or collapsed, the ball is the easiest thing for the vacuum to collapse due to it being rubber.
try back blowing your lines.
rob

 

[WAVENBYE2]

Re: engine will not run under a load with inboard gas tank

It still sounds like your noy allowing air into the tank, are you opening the air valve to allow air to enter in when you run the engine? I know you said vents are new but any time I have seen the bulb collapse like that, it was because the valve wasn't open. Oh what is that called, help me out, brain fart. Anti-syphon. it allows the air to flow.

 

[Silvertip]

Re: engine will not run under a load with inboard gas tank

There are a number of things to look at. 1) the anti siphon valve, 2) clogged screen on the end of the pickup tube in the tank, 3) you mentioned crud in the tank. There is nothing you can add to the tank that takes care of that other than a shelf full of snake oils that don't work. Drain and clean it.

 

[86bayyliner]

Re: engine will not run under a load with inboard gas tank

Thank you for the replies.... There is no restriction on the vent hose.. and as far as the check-ball.. were is that located? i have 2 fuel pick ups on the tank but im only using 1 of them.. the other is probably if i had twin engines... is the check ball located at the fuel pick up?? there wasn't crud in the tank it was some black sediment but not alot but obviously enough to clog the fuel pick up.. the fuel pick up is aluminum and is welded onto the tank but do you think that i can bend the pickup tube to get it away from the bottom of the tank .. ?? bend it just a little not alot.. let me know

 

[WAVENBYE2]

Re: engine will not run under a load with inboard gas tank

How old is the primer bulb?? could it be to soft?? what diameter hose are you using?? could try a size bigger diameter hose with a new primer bulb too. Just trying to help with the troubleshooting

 

[Silvertip]

Re: engine will not run under a load with inboard gas tank

This is what the anti-siphon valve looks like and it is the fitting on which the fuel line is attached to at the tank end. Do not bend the fuel pickup as you may break it off. Remove the anti-siphon valve and blow backwards through the tube to clear it. But if the gunk is still in the tank, it will just plug again.

 

[MDJ1016]

Re: engine will not run under a load with inboard gas tank

I am having a very simialr problem as to what you have/had. Did you ever get a remedy to your problem? My boat is an 1986 with a 350 Merc in it. 44 gallons stainless steel (could be aluminum...) tank. See my recent posting for further questions, I am stumped !