Prop speed loss

[MB Guy]

I was travelling along rice lake today hovering around 3500 rpm's, went through a weed bed and all of a sudden the rev's went through the roof and the boat just dies.

There were weeds so tight around the prop it took 10 minute to clean it up. the engine till run fine and you can hear the forward and reverse engage, but prop spins but has no torque barely churns the water.

Some guy said shear pin? possible?

Hope you can help!

 

[Frank Acampora]

Re: Prop speed loss

Depends upon the engine. Could be a shear pin--but only if your engine uses a shear pin prop, could be a spun hub. More info--Engine brand and size please.

 

[MB Guy]

Re: Prop speed loss

Mercruiser 898 i/o

 

[steelespike]

Re: Prop speed loss

My guess is you spun the hub.From your description I think if you pull the prop and look at the hub you will see evidence of the rubber hub coming apart. You could put a waterproof line across the hub and try the prop if the line is broken you have a spun hub.A prop shop can repair and test it as well.

 

[craze1cars]

Re: Prop speed loss

If it's not the prop hub, it's probably the engine coupler.

If boat is out the water, put it in gear (engine off), and try to turn the prop by hand. One direction is should go click/click/click (normal)...the other direction it should not turn...or turn very very difficult because you'll be turning the whole motor. If you can do it in the "hard" direction easily, watch the prop shaft and see if it is staying still as you do this. If yes, you have a spun prop hub. If prop shaft is turning with the prop, and it's easy to turn, then your hub is probably fine and the slipping is most likely occuring within a spun engine coupler.