Engine will spin up in RPMs boat hardly moves

[Jeff6917]

Hi guys, I have a 1996 mer cruiser 4.3l with an alpha 1 gen 2 outdrive. Last lake trip I put the throttle down and could only achieve 8mph. After I messed with the trim a bit I was able to get it up to speed with a 30 sec to 1 minute latency.

I checked the hub and it is not spun. I am at a loss as to what the problem could be. Any ideas?

Jeff

 

[alldodge]

Welcome
Most likely its the engine coupler. Did you smell anything like burnt rubber?

 

[flashback]

Maybe try another prop.

 

[Jeff6917]

Welcome
Most likely its the engine coupler. Did you smell anything like burnt rubber?

I did not smell burnt rubber, would I have smelled it in the water?

 

[Jeff6917]

I did not smell burnt rubber, would I have smelled it in the water?

 

[alldodge]

I did not smell burnt rubber, would I have smelled it in the water?

Normally yes, the coupler is on the back of the motor.

Without more info it's either the coupler or the prop hub.

 

[Grub54891]

Did you mark the hub on the prop then run it, and check if the marks still line up? Just grabbing the prop and trying to spin it by hand doesn’t work.

 

[cyclops222]

Rev it up and rubber / plastic softens / melts. Stop And it rehardens. Sometimes Do not use the boat until the part is changed.

 

[tank1949]

You may have to take prop to a good shop and pray it is defective. If not, lock motor from spinning, best way. Remove prop and replace lock nut with a couple of jam nuts. Using a breaker bar and proper socket, try turning prop shaft. Good luck.