Possible Fuel System Problem?

[GaryO]

1991 Evinrude 150 Intruder
E150GLEIS With VRO2

I'm having some concerns about the fuel system on this motor. When I go to start it I pump up the bulb in the fuel line but it never becomes firm or hard. This has all new fuel line w/bulb and the check valves on the two fuel tanks are good. There is no fuel leakage anywhere and no fuel leaking from the carbs. I also have heard that the VRO pump could have an internal leak and should check the line going to the pulse limiter. No leak and dry also.

When starting I always have to pump the bulb about 20 to 30 times. The motor runs rough at idle or any speed up to 1/3 throttle. At idle it REALLY jerks around and will turn its self sideways, I keep a bunge cord on the steering wheel to keep it straight when starting. Above 1/3 throttle it smooths out and runs great. (It is a gas hog also, I know, its standard for this type of monster. It REALLY is thirsty) Two 18 gallon tanks in a few hours running under 3,000 rpm.
Any thoughts of where I should look, other than shopping for a newer unit?

 

[rtek816]

Re: Possible Fuel System Problem?

Garyo,

Get a piece of 3/8" clear fuel line and temporarily place it between the bulb and the thru hull fitting or directly to the anti siphon valve. I couldn't find 3/8" and used 5/16" from the local Harley dealer. Turn the bulb vertical (arrow to the sky) and pump it up. Does it fill the clear line with solid fuel or does it bleed back to the tank? The pump needs fuel to operate correctly, if the line is full of air you will experience poor performance at low speeds. Did you replace the bulb w/ a Tempo? I think they are junk and would try a Sierra brand that seems to be better for me. The one way check valves do fail (again letting the fuel bleed back to the tank). Get to the point of a firm bulb full of fuel and you may solve your problem. Pumping it 20 or 30 times without a firm bulb is probably your issue.

 

[GaryO]

Re: Possible Fuel System Problem?

Hi Rtek, the bulb was a Sierra and new last year. I had the same problem in the past. That is why I replaced all the fuel lines to the motor. The check valves are external to the tank and do not allow any back flow to the tank(s). When pumping the bulb fuel is going to the engine, I just don't know where! Runs as smooth as silk at higher RPM and no fuel restriction alarm. I'll have to take a good look at the fuel flow diagram in the service manual to try and figure this one out.

 

[63Sport16]

Re: Possible Fuel System Problem?

GaryO, from you description, it sounds just like a bad check valve in the primer bulb. I see you replaced the primer last year, but that doesn't mean it isn't faulty. Try this first, point the primer bulb with the arrow upwards and pump the primer to see if it hardens up. If it does, bad check valve in primer bulb.
If that doesn't work, disconnect the fuel line from the motor, plug the end of it, then try and prime the line using the bulb. If the valves are good in the primer bulb, it will harden up. At that point at least you will know it's in the engine fuel system. If you do get it pressurized this way, TAKE CAUTION when releasing the plugged line so you don't take a fuel shower.