Motor revs fast, prop turns slow

lmacedo

Recruit
Joined
Oct 2, 2009
Messages
2
I have a 1978 200 hp Merc. I was cruising at about 30 mph when the motor started to rev higher, but the boat slowed down. I could get the boat to go about 2-3 mph at about 1,000 rpm, but it wouldn't go any faster at higher rpm's. What is the probable cause of this?
 

Fuzzytbay

Chief Petty Officer
Joined
Jun 6, 2008
Messages
557
Re: Motor revs fast, prop turns slow

My thoughts are for you to inspect the bottom end. Start with the prop itself.Make sure its not stripped on the splines, and the hub is ok. If that is ok, go to the gear assembly. Last and most likly least would be the driveshaft.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Motor revs fast, prop turns slow

If you have a spare prop, put it on and retest the boat.

Chances are the rubber hub between the prop and its inner splined collar, is slipping and due for a replacement hub to be pressed in by your local prop shop.
 

lmacedo

Recruit
Joined
Oct 2, 2009
Messages
2
Re: Motor revs fast, prop turns slow

Thanks a lot. This makes sense and should be easy to fix.
 
Top