1974 Johnson 50HP won't run at idle speed

yoda

Recruit
Joined
Aug 18, 2003
Messages
5
My 1974 50 HP Johnson Model 50ESL74M S/N 43775 will not run at idle speed. High speed ok. It appears the problem is in the lower cylinder. I can adjust the low speed jet (even shut it right off) and it makes no differnce. There is oil residue in the exhaust-it burns a lot of gas.<br />I changed the lower ignition coil thinking it was ignition. It made no difference
 

Reel Appeal

Chief Petty Officer
Joined
Aug 19, 2002
Messages
566
Re: 1974 Johnson 50HP won't run at idle speed

Sounds like time for a carburator overhaul? or two...
 

yoda

Recruit
Joined
Aug 18, 2003
Messages
5
Re: 1974 Johnson 50HP won't run at idle speed

Thanks for the reponse to my problem. This will be a simple fix. Just as a side line, a couple of friends of mine (both mechanical types) seem to think it could be a leaking lower crankcase seal.<br />What do you think? What might be the symtoms if this were the case?
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: 1974 Johnson 50HP won't run at idle speed

I believe the odds are quite a bit higher that the carb is the problem.<br /><br />Take the low speed needle out and blow compressed air though it. The reinstall the needle and try it.<br /><br />IF it clears up...take the carb off and finish the job properly.<br /><br />TMD
 
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