Grease on driveshaft

[Seafox17]

I changed my waterpump on my 90hp Yamaha 4 stroke. When I was greasing the driveshaft splines, I put grease on top of the driveshaft as well. Will this cause a problem?
I've since read this was incorrect and may cause "hydraulic lockup." I cranked up on the water hose and peed water just fine. I haven't had it in the lake yet.

 

[boscoe99]

If the lower unit went back onto the motor easily then more than likely there is not problem.

Putting grease on the top of the drive shaft can cause a problem. Not will cause a problem. It depends. Mostly on the amount of grease that is on the top.

For what purpose was the top of the drive shaft greased anyway?

 

[Seafox17]

I didn't really grease the top on purpose. I just wasn't very careful about not getting any on top. I later read on a post to make sure not to get any up there. I really appreciate the reply. I'll just leave it be and take her to the water.

 

[GA_Boater]

Just a confidence vote, Seafox - If it went together, you're OK.

Too much grease fills the cavity above the driveshaft and the excess has to work it's way down past the splines making it harder to fully seat the lower unit.

Welcome aboard and time to go test her out. :smile:

 

[99yam40]

I can make dropping the ;lower unit also difficult some times if there is enough suction

 

[Sea Rider]

Drive shaft splines must always be slightly greased with a proper water grease, that way will be able to pull lower leg much easily anytime.

Happy Boating

 

[jimmbo]

Grease, like liquid, is not compressible. When applied to the top of a driveshaft it can prevent full insertion of driveshaft into crankshaft. In addition, even if the shaft does install completely doesn’t mean all is good. It may have just got gotten in by putting an upward preload on the crankshaft and a downward preload on the pinion gear

 

[Seafox17]

Motor operated normal when we took it on the lake. I guess I didn't get enough up there to cause a problem. Thanks for the replies. I'll know next time to be more careful.