Old Merc - prop should fit but doesn't!

[el toro]

I just got a 1978 Merc 800 with no prop on it. I was going to use the props from my 1986 Merc 115 but they will not fit down the splines of the 80hp. I've called a couple Merc shops in the area and they both say that they should fit. What gives?? Any suggestions? Thanks.

 

[steelespike]

Re: Old Merc - prop should fit but doesn't!

According the the prop store sku numbers they user the same prop.
I would suspect that the shaft on the 800 is messed up or ,unlikely,
the props are messed up. Coming from a 115 the pitch may be wrong anyway.
Dependin on what they were on.
Maybe a dealer would let you try a new prop.
I would start by being sure the shaft clean.Could have some corrosion or dried lube
on it.Perhaps the shaft is bent or has a ding on one or more splines.

 

[Bondo]

Re: Old Merc - prop should fit but doesn't!

Ayuh,... Are you using the Right thrust hub,..??

 

[el toro]

Re: Old Merc - prop should fit but doesn't!

Thanks for your responses guys. The propshaft appears to be straight but its not the problem anyway, I can barely get the splines to mate even an 1/8th of an inch. It almost seems like the wrong hub yet the spline count is 15 on both the shaft and the prop. I was checking it again today and there might be a slight burr on a spline or two on the shaft. I may just take the dremel tool to it and see if that affects anything, if not then I guess the service shop will have to tell me whats wrong.

 

[steelespike]

Re: Old Merc - prop should fit but doesn't!

Have you tried to put the prop on backwards? Just to see what happens?