drive shaft slipping in midshaft

[Pablo]

Anyone have an idea how to diagnose if the driveshaft is slipping inside the midshaft? My pump's been through hell in the last month. Lots of torque, heat, ice, oils and finally had to cut a prop off to put new one on. From a visual inspection the splines looked o.k. when I reinstalled it. I did have to shim my midshaft forward in hull about a 1/16 or so with washers to get the coupler gap correct. On installation the splines seemed to fit well. I finished my build this past week and put it in water yesterday. I'm getting horrible hook up with the new prop (hooker 9/15). I was questioning whether the impeller was loose, but I pulled the ride plate and turned the impeller. It seemed snug on drive shaft. I used all the same shims on pump/engine/midshaft for the install, but am questioning whether it's the driveshaft slipping in the midshaft. I didn't install the pump first, but last after engine/midshaft alignment. Can you feel the splines slipping or grinding on each other or does it feel like cavitation or loose prop? I've got the pump off to run dual cooling now and could do a re-alignment now, starting with pump on first then midshaft and engine last (if that's the correct way).

 

[stanton]

if your driveshaft is stripped youll know it. sounds like a cavitation problem.

 

[Talsivar]

when the shaft strips out your not going anywhere. also instead of shimming the short shaft tap the back of the shaft to move it forward. then when you have it off you can see how the splines look inside. but if your long shaft splines look good with no wear your probably good.

 

[Pablo]

Here's pictures of my driveshaft splines. I didn't notice any metal shavings or evidence of drive shaft slipping. I splines look a little worn on one side. There is a rub line next to the end of my thumb that appears new ( I don't remember it from before). Should I pull engine and install pump first and work forward to midshaft and then engine or since I didn't notice any evidence of drive train slipping look at the wear ring/seal/pump shoe fit? I've got one of snowxr's metal pump shoes with my OEM seal and old wear ring. Could the wear ring be out of tolerance with impeller making the low end thrust poor? The prop hook up is better in midrange and when ski is moving.

 

[Pablo]

Do you boys grease the spline connection between drive and mid shaft? Should the pump shoe be sealed to the hull with silicone before securing with screws?

 

[Idok]

Do you boys grease the spline connection between drive and mid shaft? Should the pump shoe be sealed to the hull with silicone before securing with screws?

yes grease the shaft, absolutly..


yes seal the pump shoe, but 5200 is better...then run a bead on the inner edge of the pump shoe as well..

make sure you also silicone the midbearing housing to the firewall, and check that the rubber seal is not separating

 

[LBE]

That driveshaft is worn, but not stripped yet. I pack the midshaft with grease before putting the driveshaft in.

You problem sounds like the pump seal or "packing" is not allowing the pump to pressureize.


Start shopping for a driveshaft and mid shaft, from my expierence, when they start to go, they don't last long.

 

[Wave Chaser]

Those splines are good enough they are not slipping.

Sounds like your sucking air in somewhere. Either around the pump shoe or the seal.

 

[Motorheads5]

3M 5200 on the pump shoe is fine, but do not use it on the pump you will never get it out again !