4hp Evinrude model 4336 C Stalls after 5 - 10 mintutes, will restart most times

[zzr7ky]

I am pretty handy with marine engines. New to smaller outboards. I inherited my childhood favorite 1973 Evinrude 4hp 4336 C.

I replaced the fuel lines, bulb, installed a good sized fuel filter in the fuel line, and.... no start. It started when fuel was sprayed into carb. So I went through the carb. Cleaned, reassembled. backed the low and high speed adjustments off 1 1/2 turns (560 degrees) and it starts!

The problem I am having is after 5-10 minutes it will falter and stall. Higher rev/ speed doesn't seem to matter. Pumping the fuel bulb once it starts to lose power doesn't affect it. Sometimes on re-start it will just run on one cyl.

I am unfamiliar with the ignition system.

I can say the cyl head is cool to the touch even after running a while.

Any thoughts?
THANKS!,
Mike

 

[Chinewalker]

I would go through the ignition system. Possible cracked coil breaking down once warm. Possible bad condenser, can also be affected by heat. Clean and gap points to .020".

You mention pumping bulb doesn't help, but I'd check the gas tank vent for good measure.

 

[oldboat1]

Pretty easy old points ignition. Want to use a harmonic balance puller to remove the flywheel, then check for cracks in the coil coatings (replace if cracked). I usually just replace points and condenser at that point -- points cleaned with some alcohol or lacquer thinner, then set to .020 as stated. Good it's running cool, but probably time to replace impeller just to be safe. High speed carb needle (lower needle) usually ends up between half and 3/4 turn open. Low speed one turn or so -- varies.

Guessing probably a coil problem, like Chinewalker suggests.