Help please!!!!!

[RooSmith]

I just bought a boat with a early 70's johnson 20hp motor took it out and idles great runs at low speeds great but once you give it gas it stays running but barely moves, i took it to a boat mechanic and had a compression test and over 100psi in both cylinders also had carb cleaned and fluids changed??? if anyone can help it would be greatly appreciated i really want to get it working

 

[bktheking]

Re: Help please!!!!!

Pull the prop off and inspect the drive pin, may not have one or it may be broken.

 

[Rick.]

Re: Help please!!!!!

"stays running but barely moves"
Can you explain that? Does it rev high but not move or does it get sluggish and barely move. How fast is barely? Does it move well at slow speed? Try to give as much detail about your specific concern as is reasonable. Remember we haven't seen what you've seen so we rely entirely on what you tell us. Best of luck. Rick.

 

[RooSmith]

Re: Help please!!!!!

Thanks for the responses, sorry if i did not go into detail enough, it runs fine until about half throttle then it bogs, sounds rough, i thought it wasn't getting enough gas i checked the hose and tank and vent and all seemed to be working well