100hp merc prop feels like it spins out

[jmymarch]

I have an 89 searay with a 100hp mercury motor produced for this boat. It starts fine and runs well at low idle but when I push throttle to full it lags like its missing shifting. When it does go up to full throttle at about 3000rpm it jumps to 5000rpm the prop feels like it spins out (bushing??). The motor doesn't seem to skip except with that increase in revs. If it lags I go back to nuetral and try again; so far it seems to be the worst when the engine is cold. I put an after market prop on after hitting a stick early in the season and destroying a prop that was very brittle and just broke up but that certainly could have done interior damage. Any help would be great.

 

[MI Hokie]

Re: 100hp merc prop feels like it spins out

Sounds like the prop is cavitating. This is where your prop loses "bite" with the water. You may need a prop with a shallower pitch (lower pitch number) to handle WOTs from stopped. This will decrease your top speed but give you a better hole shot.

 

[jmymarch]

Re: 100hp merc prop feels like it spins out

hi thanks but it is not cavitating it's flat out loosing power. The prop spins out but the power drops out like it's not hitting second gear. Is there a gear box that could be miss shifting?

 

[gregpro50]

Re: 100hp merc prop feels like it spins out

It sounds like it might have spun the hub bushing. There is no shifting except for forward and reverse. Switch to a spare prop or have the bushing replaced on the prop you are running.

 

[jmymarch]

Re: 100hp merc prop feels like it spins out

I agree and am going to purchase an new prop and bushing. Any ideas on the intermitnant loss of power as I accelerate? I just replaced the throttle and clutch cables in the boat.