70 HP Johnson with little power

Ritz

Cadet
Joined
Apr 24, 2002
Messages
7
OK got my budget boat on the water for the first time since I bought it. Starts fine, Idels great, runs up smooth but when I give it full throtle it runs like I've only got it at about 1/3 power. Checked throtle linkage and its opening the carbs all the way up. Got spark to all three cylinders. Fuel filter is clean. Gas/Oil = 50:1 Dosent look like its sucking air anywhere. Dosent heat up and runs great just no real power. Correct prop. People might think Im crazy but there isnt that nice high pitch 2 stroke whine when I open her up. Acts like its only at partial throtle.... Help... :mad: <br /><br />The only thing I can relate it to is model airplane/car/boat engines. You know the kind with the little needle valve adjustment. If you have the engine wide open and adjust the needle valve so its way rich the engine looses power. Thats how my outboard acts.<br /><br />Can my outboard be adjusted way rich thus not delivering its full power? Can the timing be off a few degrees? Would that even affect it? Dont know.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 70 HP Johnson with little power

Hi, Ritz.<br /><br />You probably have a carb problem. It could be a stuck float (running too rich) or gummed up jets (too lean, not firing at all). My money would be on the gummed up jets.<br /><br />Good luck. :)
 

Ritz

Cadet
Joined
Apr 24, 2002
Messages
7
Re: 70 HP Johnson with little power

OK, I think I can tear them off and clean them up, anything I should know before I do this???
 
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