1982 15HP Evinrude dies around 2 min during fast idle

[Slyhog2020]

I have rebuilt the carb,replaced fuel pump with new one, new tank hose both bought from IBoats and fuel hoses but the motor will only run approx. 2mins and then the fuel bulb needs to be pumped in order to keep running. I also switched out tank with a proven working one. I’m starting to pull out what little hair I have!

Thoughts?

 

[pointblank1000]

Sounds like the vent on the tank is closed. Just remove the cap from tank and see if that helps.

 

[tphoyt]

It does sound like your running out of fuel and my first thought was the tank vent as well.
I know you said the tank is known to be good and the hoses have been replaced.
So if it’s not a vent issue then back to the carb. Yes it was rebuilt but how well was it cleaned? Just a can of carb cleaner or a full tear down and soak in parts cleaner or similar before reassembled?

 

[racerone]

The fuel pump works with PRESSURE pulses from the crankcase.----There may be an issue there.-----Check o-ring on hose fittings.----Or run with another tank and hose.

 

[Jeremy1986]

Check your compression. If compression is low then the fuel pump will not work properly as it not strong enough for it to work.

 

[Jeremy1986]

Check your compression. If compression is low then the fuel pump will not work properly as it not strong enough for it to work.

Also check all fuel lines to make sure they are tight. Any loose lines will suck air and prevent the fuel pump to work properly.

 

[OptsyEagle]

Not sure if you are testing this motor on your boat or on a boat stand with a bucket of water, but if the motor is on a stand and the tank is on the ground, try lifting the tank a little higher in elevation and see if that helps. I would think a new fuel pump would be able to pull the fuel as high as a motor but certainly the older pumps sometimes get a little tired. On the boat the tank is usually at most a foot or two below the fuel pump.

Other then that, if you don't see fuel leaking out anywhere I would suspect it is either something with the hose or tank, since it seems to work when you pump the primer and you have a new fuel pump OR the inlet valve on the carburetor is sticking closed for some reason and requires the extra pressure of the primer to dislodge it.

 

[racerone]

Cylinder compression has nothing to do with operation of the fuel pump.

 

[oldboat1]

Check the top of the head for overheating (too hot to touch?) The hose clip to the motor might be the problem. Might try pushing in the ball with a phillips screwdriver (holding well away from your face), then reattach and try.