Super Jet Possible Striped Drive line?

[227]

On my last ride I landed a little inverted on a Backy and clearly did some damage. Not a pancake (I've done plenty of those) but just came in hot. When I came up my ski was grinding and making all sorts of noise. Gave it a blip of throttle and I was clearly in neutral, so I thought I'd broken my coupler. I had to get towed in. When I got to shore a quick inspection told me my coupler was OK, but that I had broken some motor mounts. When tearing it all apart I discovered that I had actually broken 2 motor mounts, and the remaining 2 broke when I removed the motor (Not when I was riding). My coupler is OK, so I'm thinking striped dive shaft splines, however when I pulled the pump my drive shaft splines also appear to be OK. When it happened my ski was running and wasn't going anywhere, even after giving it throttle. So I guess my question is; Do the interior splines on the midshaft strip out without really damaging the drive shaft splines? Unfortunately you can't really see the interior splines on the mid shaft in this picture but to me my Drive shaft looks OK or am I reading it wrong?

Does this look striped?


Here's the Mid Shaft, I know you can't really see anything

 

[Matt_E]

Drive shaft splines look mint.

 

[deftons56]

Try to get a cleaned up look at the mid shaft.

 

[Dmac80sc]

Did you check your throttle cable to see if that had broken? Did the motor rev up when you hit the throttle or did it just not do anything?

 

[SXR-FOREVER]

Impeller come loose?

 

[227]

I'll clean up the Midshaft tomorrow but it seems like If I did strip the splines in the midshaft then at least some damage would have occured to the drive shaft splines, it was making a pretty nasty grinding noise. I guess its possible that my motor could have shifted forward and disengaged the couplers but thats unlikely that it would slide back into place. Also I never hit bottom, and only two MM were broken and I run Kenny Keepers. The throttle cable is new. I was in fairly good sized surf at the time so when I gave it gas the engine responded (Reved up) but it didn't go anywhere and the grinding noise was pretty bad, bad enough that I shut it off immediately fearing I would do more damage leaving it running. How can a impeller come loose? Arn't they threaded so that the rotation of the drive shaft makes them tighten? I'm scratchin my head on this one....

 

[Honda118]

Put a q-tip or popsicle stick or something into the mid shaft to see if you got any metal shards in there

 

[TJR]

Did you snap a shaft? If you striped the splines in the midshaft, Im sure you would have seen more metal then you like, when you took it apart.

 

[Big Kahuna]

When your motor shifted it changed the angle of the couplers and mid shaft in relation to the drive shaft. Most likely rounded out the mid shaft splines. If your prop had come loose odds are you would have gotten some momentum when you tried to rev it up. Prop would have tried to spin back on. Only other thing would be your coupler might have stripped, rare but possible. What kind? OEM would most likely shatter whereas billet would not give.

 

[Tommygunz]

Just put the midshaft on the driveshaft and try to turn it.....if it moves then there's your answer. I went through a bunch of mids and drives last year and sometimes the mid would strip without driveshaft damage but not too often. Good luck man.

 

[BruceSki]

I have seen the coupler threads shear off but the coupler still stays kinda stuck on the midshaft. Had the ski running and idling and the midshaft side coupler was spinning around the midshaft where the threads should be.

That was from a swollen pump liner on startup and broke the weakest link. The threads on the midshaft/coupler.

This should be pretty easy to spot with a close inspection of all parts. Did you spin the driveshaft by hand? Maybe grenaded the pump bearings?

 

[Matt_E]

I've seen a Kawi strip the threads on the coupler.