82 Johnson 235 low RPM under load

Mark_Alan

Cadet
Joined
Aug 6, 2012
Messages
9
I have a 1982 Skeeter Starfire SF-175 18-ft bassboat with a 1982 Johnson 235 hp. When running in neutral using the fast idle the motor revs up fine, however when in gear at WOT the motor will only run about 3,000 rpm's.

Last week it ran GREAT. Loaded it on the trailer and brought her home. When I got home I noticed the propeller nut was loose (you could turn it with your fingers) so I torqued it to 70 lbs. Could I have over-torqued the prop nut causing this problem? If not, any ideas?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 82 Johnson 235 low RPM under load

The prop nut has nothing to do with it. Try starting with a compression and spark test. Spark should jump a 7/16 " open air gap.
 
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