1977 Evinrude 55hp

[PPaine]

I recently purchased a 1977 Evinrude 55hp motor for my 16ft boat. I did a compression test 127 and 130 psi for the two cylinders. The problem i am having is when it runs on the water for 10-15 minutes, it just shuts off. Wait 10 minutes, it starts and runs for a few minutes then dies again. When it initially starts (after warm up) and give it gas, motor runs great until the 10-15 minute mark. Primer bulb is still fairly firm when it dies. Are there any ideas on what it could be?

 

[Crosbyman]

start with the basics... when dead do you have sparks ?

is it pumping water properly…..

how is fuel delivery….is the tank venting properly …..try running with no fuel cap on the tank if ok vent is plugged

how about the carb….has it been service lately ???


could be component failure due to heat and that will show up in the spark test ...could be coil failure etc...

try a new hose some hose go bad due to inner lining collapsing causing fuel restriction


could be power pack going flaky ... mine drove me nuts on Merc Classic 50 or stator ...again check for sparks 1/2 long
when dead

 

[PPaine]

Crosbyman. I redid water pump and it seems to have helped. It ran on muffs for 45 minutes at 45 degrees with no issue ( 15 mins in icy lake prior). Impeller wasnt messed up though, only missing a gasket at the base of water pump assembly. Carbs are fine, and spark is great. Could this just be a gasket issue? Or potentially powerpack failing at intervals

 

[Crosbyman]

well………. it is wait and see for now. if the powerhead got to hot who knows which component went flaky ...coils powerpack ?

Infra red heat guns are dirt cheap now… 25$ you could always scan the powerhead for hot spots but if things look up it may have been all heat related from lack of proper cooling ...if so you ra re lucky it did not seize up


maye your pump was sucking some air ..give it a run and see now that you have it on with the gasket