50esl74m 1974 50hp Johnson need help

DMG509

Recruit
Joined
Apr 30, 2009
Messages
5
First off...Hello everyone, I love this site nad all the info.
I'm going to explain what i've done so far and the symptoms.

motor ran 3 weeks ago. not great but had good WOT-RPM and boat moved

So far we've changed, Coil (lower) was cracked, new plugs (the orig were hard to find --UL77v champion no gap, hook for spark to jump to?) shows the same plug in the manual. New solenoid, New batteries, new control box and cables. New stator and harness, new fuseable link, new starter
2.after all this work the boat will not run full speed, starts great, idles high with cold start choke pulled up as it idles down is will miss a bit, then when you shift into forward it stalls, i can keep it rev high and put into forward and goose it it will go but only half throttle, I pulled cowl off while running and i can push the carbs open and it gets a little more power but starts to bog out.
3. the plugs keep getting black.
4. smoking a bit at start up


Thanks for the help guys.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 50esl74m 1974 50hp Johnson need help

You've described a engine with fouled carburetors, clean and rebuild them using complete carb kits. Kits available on this site, NAPA, dealership, marine stores.

Champion QL77JC4 s/plugs might be a better choice, gapped at .030 or .040, whichever works best for you.
 
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