What is a spun prop??

[gmarshall43]

I have a 1967 Merc, 9.8hp model 110. I had it out on the lake and it ran fine. When I went to use it next, it started fine and went into gear ok. But when I throttled up, the motor revved up really high and didn't go anyway. When I turn the throttle down to a slow speed, I was able to get back to the dock. I was told I have a spun prop. What is this and what do I need to do to get it fixed?

I have a 1974 9.8hp Merc that looked like it had the same prop so I tried using it but had the same results. Could both props be bad?

Thanks

 

[diaric]

Re: What is a spun prop??

could be, but it doesn't usually happen that often, both motors are older so its a possibility. there's a rubber hub between the splined shaft mount and the outer ring with the blades. its a shock absorber for your drive gears. when the rubber breaks free, its spun. to test, mark a line across rubber and prop, take it on the lake, and see if it moved out of position. they can be rebuilt for 50 -75$

 

[Laddies]

Re: What is a spun prop??

Yes they could both be bad, it's always a good idea when you have the problem to mark the prop and hub with a marks alot and try it to see if if slips by checking the marks after use

 

[JB]

Re: What is a spun prop??

The prop is attached to its hub with a rubber sleeve, GM. When this rubber interface fails we call it a spun prop.

Any prop shop can re-hub it for you.

 

[JB]

Re: What is a spun prop??

Dang!! You guys are fast.

 

[diaric]

Re: What is a spun prop??

think we all hit enter at same time lol

 

[gmarshall43]

Re: What is a spun prop??

Thanks for the education. I remember a burnt smell and I turned the motor off thinking it was the power head. Probably that rubber sleeve??

The prop has two fins on it. I was told that a three fin prop would make the boat go faster. Is this true?

Thanks again