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'81 Johnson 140 Max out at 2200 RPM

J

john55c

New member
Hi all, new to the forum, and having issues with a 1981 Johnson 140hp. Last year, when we first purchased the boat, the previous owner said the boat would not go full throttle...he was right. When we pushed the throttle to full, it would go to about 2800RPM, then gradually (read slowly) creep to 4000RPM. Specs say that these engines should run WOT at 4500-5500.

We had to take the engine off over the winter to do some transom work, and it now does 2200 RPM. It will rev up, but will not run at higher RPM. It seems that at WOT, while the cable is extended all the way, I can still rotate the carbs another 3/4". Any ideas? This engine is on a 1980 Glastron SSV176, so should fly with this engine (my father has a much heavier 18' boat with a 115 Yamaha and it does about 32-33mph).

Any ideas/suggestions would be greatly appreciated!
 
Do a compression test and check that you have spark that will jump a gap of 7/16" at all 4 cylinders.------------If those are good then look at fuel carburetion issues.-----------Those are the first " no money spent " tests to do.
 
racerone said:
Do a compression test and check that you have spark that will jump a gap of 7/16" at all 4 cylinders.------------If those are good then look at fuel carburetion issues.-----------Those are the first " no money spent " tests to do.
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Thanks we will try the compression test tonight and will report the findings!
 
Compression test yielded 115 to 130 in all 4 cylinders. We just took the carbs apart last week, cleaned them, and put them back on, so there didnt seem to be any gunk in them....
 
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