1994 120hp johnson o/b no power/rpms under load??

[skipper6567]

Hi All,
I am a pretty good mechanic and hope I can help out some of you guys. I have a buds engine that has 140psi in al 4 cyls,runs smooth at idle,will scream up when no load on it. Hit the water and push throttle up and it's like you aren't moving the throttle. It is openning the carbs and advancing the spark. I had him run it out of a 6 gall external tank. He used 6 gals in 15 mins??under a load and never got more than 15oorpm. It doesn't seem to caugh,just no power? plugs are clean,should I hear noise,like air? when I pump the ball into a bucket? it has a checkvalve on the tank.could I be sucking air?? is there any tests for the vro /fuel pump. He had a "mechanic" take it for a week.1700.00 later he was told cracked block,could not tell him where the crack was???!! only charged him 1k for labor!! what a sport!!!he disasembled the entire engine,new engine gaskets set complete.. still has the same problem..power pack was done last year..any input would be great.I am going to drop it in the water thur night to see it run under a load. temps are good..Thanks Skipper

 

[JB]

Re: 1994 120hp johnson o/b no power/rpms under load??

Sounds to me like one or two carbs are flooding like crazy, skipper. That would account for the huge gas usage and those one or two cylinders not making any power.

What a multi-cylinder 2 stroke will do with no load can be very misleading to someone used to 4 stroke engines. They will start, idle and rev like a healthy engine on half of their cylinders.

Check those carbs for stuck floats, needles, etc.

 

[tashasdaddy]

Re: 1994 120hp johnson o/b no power/rpms under load??

agree

 

[kenmyfam]

Re: 1994 120hp johnson o/b no power/rpms under load??

And seconded !!!!