Fuel problem

[bonz_d]

1978 35hp Evinrude. Motor runs fine @ WOT. Will not idle for long periods of time w/o running out of fuel. Same thing after shutdown. The bulb will be soft.

I recently replaced the fuel line and the 2 connectors to the tank and the motor which has seemed to make the matter worse. I am using a plastic tank and the fitting that goes into the tank swivels fairly easily. That shouldn't be causing the problem should it? I have looked at all the hoses and fittings inside the engine and all seen tight. So where else should I be looking for a leak?

Thanks, bonz

 

[countvlad]

Re: Fuel problem

1978 35hp Evinrude. Motor runs fine @ WOT. Will not idle for long periods of time w/o running out of fuel. Same thing after shutdown. The bulb will be soft.

I recently replaced the fuel line and the 2 connectors to the tank and the motor which has seemed to make the matter worse. I am using a plastic tank and the fitting that goes into the tank swivels fairly easily. That shouldn't be causing the problem should it? I have looked at all the hoses and fittings inside the engine and all seen tight. So where else should I be looking for a leak?

Thanks, bonz

soft bulb is normal.... collapsed isnt.....

when was last time taht a decarb or carb rebuild?

 

[bonz_d]

Re: Fuel problem

Carb was last summer.

If I bump up the throttle just a little bit it wont do it and it runs smooth @ a closed position until it runs out of fuel. Pump the bulb a few times and it will start right up.

 

[countvlad]

Re: Fuel problem

Carb was last summer.

If I bump up the throttle just a little bit it wont do it and it runs smooth @ a closed position until it runs out of fuel. Pump the bulb a few times and it will start right up.

im a little confused..... does it die while it idles? try to pump the bulb while its either dying or when you think it might stall....
if you can maintain the motor to run while you prime the bulb then its probably the fuel pump.. also check for any leaks in the fuel lines....

 

[bonz_d]

Re: Fuel problem

Sorry, just reread my last post and it even confused me.

Yes, it dies while at an idle and after running if I shut it off I have to reprime the bulb before it will start. While running if I idle it up just even a small amount it will stay running.

Now after reading the replies and thinking about this it does seem to make more sense to be a pump problem instead of a vacuum leak as the tank is not pressurized and I can't find any fuel leaking fron the hose or fittings.

Though why would I be losing fuel pressure after the engine is shut off for even a short time?

 

[countvlad]

Re: Fuel problem

Sorry, just reread my last post and it even confused me.

Yes, it dies while at an idle and after running if I shut it off I have to reprime the bulb before it will start. While running if I idle it up just even a small amount it will stay running.

Now after reading the replies and thinking about this it does seem to make more sense to be a pump problem instead of a vacuum leak as the tank is not pressurized and I can't find any fuel leaking fron the hose or fittings.

Though why would I be losing fuel pressure after the engine is shut off for even a short time?

it is normal for the bulb to be soft while and after motor run... its soft because the pump sucked some of the fuel out of there..

i think you are confused.... if the bulb is soft thats fine...

now do this and get back with us
http://forums.iboats.com/showthread.php?t=158076

 

[bonz_d]

Re: Fuel problem

Thanks countvlad but I don't think the problem is carbon build up.

We just got back from a week long fishing trip and while we were out on the water after a few hrs of running it I found that the plastic gas tank had collapsed. So we tried it with the cap loose. No better on the idle.

Again at closed throttle it will run for a bit then die. Will then have to reprime it in order to get it to start. At just off closed throttle it runs fine. At WOT it runs fine.

Today I pulled the carb and it was very clean inside, no discoloration or deposits. Sprayed it out very well with GumOut Carb cleaner and all the passages were clear. Even the 3 low speed ports. Carb was rebuilt less than a year ago by the person I bought it from.

While I had it apart I did find that the float was off a bit and was too low. Also a couple of the fuel lines were held on by plastic wire ties! Fuel lines also looked like they were just replaced. So tomorrow I will be pulling the fuel pump and rebuilding that and also putting some clamps on the hoses.

Then we'll see if that fixes it. Did ask a few of the local boat shops about ethanol resistant hose and the all looked at me like I was stupid and they didn't know a thing about it.

 

[kenmyfam]

Re: Fuel problem

Take the fuel pump to carbs line off and crank it into a container. If it starts out with a few strong spurts and then dies off to more of a trickle it is most likely the pump. This is summising that the tank is properly vented. If it spurts consistently and strongly then the pump is doing it's job.

 

[bonz_d]

Re: Fuel problem

Thanks, very good idea. In the morning I'll give it a try after I get the clamps on and reattach the starter. Will let ya know what I find.

 

[kenmyfam]

Re: Fuel problem

Thanks, very good idea. In the morning I'll give it a try after I get the clamps on and reattach the starter. Will let ya know what I find.

Good Luck and please post your findings.

 

[bonz_d]

Re: Fuel problem

Tested the fuel pump today and it appears to be pumping OK. Though I did have to pump the bulb before it would squirt any fuel and it did pump fuel from the hose while I was squeezing the bulb. Is that normal?

 

[bonz_d]

Re: Fuel problem

Have the engine back together and test ran it in the tank. It's running better than it was but still dies out at closed throttle after a minute or so but at least now it will start back up w/o having to reprime it.

Also at least now there is no lean sneeze before it quits. Already have a pump kit for it so I might as well add that also and see if there is an improvement.

 

[bonz_d]

Re: Fuel problem

Rebuilt this fuel pump then tested it per the directions in the rebuild kit and it would not hold pressure on either side of the pump. But the pump on the motor just to test it and the same symtoms remained.

It would run for a few minutes then quit. The bulb would be completely soft/empty. Then opened up the pump where the the screen filter is and the pump was dry.

Replaced that pump with another that I had and the problem now seems to be corrected. Motor starts right up, idles well and the bulb does not go completely soft. So hopefully I now have this sorted out after spending $60.00 + for the carb kit and 2 pump kits. As the 1st kit wouldn't work as the pump at some point had been replaced with an updated model.