prop not keeping up

[marybeth]

I wrote this in another spot but think it was supposed to be here instead. Sorry if causes problem. Have a 25horse johnson motor, was running fine when all of a sudden when i gave it gas the prop seemed to not be able to keep up with the motor itself. Almost like the sheer pin is broke but cant be cause it will go in slow speeds. Thanks for any help
Marybeth

 

[ezeke]

Re: prop not keeping up

In addition to the drive pin, the propeller has a rubber bushing between the inner and outer sections of the propeller hub. The bushings are designed to fail when you strike an underwater object but over time, heat, age and oil will break them down and they slip; they call it a spun prop.

You can check for a spun prop by scribing a line across the face of the hub and, using the cotter pin as a pointer, see if the pointer has moved in reference to the line after running.

If the prop is spun, you will need to find a prop shop to repair it.

If the drive pin has broken it will be more obvious when the propeller is removed for inspection.

 

[kenmyfam]

Re: prop not keeping up

Sure seems like a spun hub.

 

[Homedad]

Re: prop not keeping up

Yeah it would be the rubber bushing inside the prop itself. Only a boat shop would be able to repair it as it has to be pressed in. My 33hp johnson just did the same thing only problem is I had to replace the prop since the shops told me it was to old.