lacking top end power at WOT 76 johnson 9.9

Jmac870

Seaman
Joined
Apr 13, 2014
Messages
53
Pretty new to outboards, had my motor on the water for first time today and it runs great except when the throttle is wide open it doesn't seem to rev high as other outboards I've used almost like it really doesn't scream like the motor should. Noticed the spark is weaker in bottom plug (doesn't jump as far as the top one but still looks blue at night). Also being not the best mechanically I have not attempted to take the carb off and clean it yet, do either of these sound like my problem? Any advice appreciated thanks
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,503
Re: lacking top end power at WOT 76 johnson 9.9

Compression test is item 1 to do.
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,471
Re: lacking top end power at WOT 76 johnson 9.9

Then cylinder drop test (pull one plug wire at a time under high idle). Lets you know if both cylinders are firing.
 

Jmac870

Seaman
Joined
Apr 13, 2014
Messages
53
Re: lacking top end power at WOT 76 johnson 9.9

Compression is about 95 psi in both cylinders
 
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