1953 john sea horse (10hp) not running full power

[earth48401]

recently my 10 hp seahorse will not run at full throttle. In neutral in revs up great hitting peak rpm, but when engaged in forward only runs at half to 2/3 power. Plugs new, fuel mixed correctly, and the plugs are not fouled after running for a while. I figure its a carburator problem???? Any ideas would be a great help!

 

[petryshyn]

Re: 1953 john sea horse (10hp) not running full power

Be sure you have:<br /><br />>spark to both plugs<br />>compression<br />>adequate fuel flow (try pumping the primer while running)<br /><br />* I assume you have a pressurized tank, so be sure the cap is tight.

 

[longdude17]

Re: 1953 john sea horse (10hp) not running full power

First before doing anything I would say have a compression test done. I sounds to me like the motor runs great while not under a load, but when You put it under load conditions(putting it in gear) you my be having a loss of compression from worn out rings or a scuffed cylinder. But then a gain you might have a dirty carb. an easy fix.

 

[JB]

Re: 1953 john sea horse (10hp) not running full power

Ahoy, Earth.<br /><br />I suspect that you are running on one cylinder, which is plenty to rev up with no load. If it starts and runs with one plug disconnected, but not the other, you have a dead cylinder.<br /><br />Your two cylinders share a carburetor, but have seperate magnetos (one flywheel, everything else is dual). The carb is probably not your problem.<br /><br />Prime suspect is one of the magnetos, not making spark.<br /><br />If it turns out that you have strong, blue spark on both cylinders, next suspect is reeds for the cylinder that isn't making power.<br /><br />Let us know what you find. Good luck.

 

[earth48401]

Re: 1953 john sea horse (10hp) not running full power

Thanks for all the help....loooks like I have some detective work to do!