Losing fuel pressure at idle

[archcycle]

1990 120hp evinrude
When I am going anywhere faster than idle I always have good pressure and the primer bulb is tight, but if I idle slow for a minute I lose that pressure and can't pump the bulb up tight again usually. Replaced the bulb and tank side connector on the fuel line to no avail. Any time I'm running like 1100+ though it's great! Ideas??

 

[jtexas]

Re: Losing fuel pressure at idle

Sorry, a little confusion here. I'm guessing it idles for awhile then dies? And the carb bowls must be empty at that point cause you've lost all your fuel pressure?

You said "...can't pump the bulb up tight again usually...." If this happened more than once, then you must have eventually been able to pump it up tight again...so...you mean you squeeze and squeeze and it never gets tight?

Then maybe what, a day or a week or a month later you manage to pump it up and repeat the process?

My initial impression is the same as yours...disconnect on the tank end or primer bulb.

My second impression is the fuel pump, isn't getting enough vacuum at low RPM, but it is at high RPM. In no way explains it's inability to get hard again after the first time. Have you tried that 36-hour tablet? Inspect the pulse line. Or heck, just replace all the fuel lines, they're pretty old by now.

That's all I got. Good luck.

 

[rolmops]

Re: Losing fuel pressure at idle

Have you tried that 36-hour tablet?

That's all I got. Good luck.

If that's all you've got,there is a problem..