what could of caused this?

[Kajun37]

the splines on my 79 merc 20hp lower unit shaft are being worn down..they are half way gone......no wonder it wouldnt go very fast lol.....

what do you think caused this and what can i do to fix it? if i change just the shaft would i have to break into the case and take everything out or would be easy to swap it out with a new one? my lower unit is not locked up and neither is the powerhead.

 

[Laddies]

Re: what could of caused this?

No grease then it's installed in the powerhead and many, many hours running. The unit must be dissembled to change the shaft

 

[j_martin]

Re: what could of caused this?

I wonder what the splined hole in the crankshaft looks like?

Also, could it be spray metalized and recut?

 

[Silvertip]

Re: what could of caused this?

Check with a local machine shop. They may be able to weld it up and recut the splines. It may not even be necessary to disassemble the unit since it could be easily heat sinked to prevent heat getting to the lower unit parts. There is a dead-center on the shaft so it could be chucked up for the machining process. If it needs to come apart, rebuilding the shaft is still an option that may be cheaper than a new one.

 

[DJ]

Re: what could of caused this?

I wonder what the splined hole in the crankshaft looks like?

Agreed.