Why did this happen to my driveshaft?!

[nick97]

I was out riding when my 701 made this awful grinding noise, ski didn't die I just couldn't go anywhere. Didn't know what it was at first but I compression tested it and it was good so figured it had to be in the pump. Took the pump off and my pump shaft looks like that, almost positive it shouldn't look like this, that noise must've been the shaft slipping? So my question is why did this happen?? Thanks

 

[Dartman]

old age
bad oring seals (2 of them) inside the mid shaft letting water wash out spline grease
when was the last time you greased it?
bad motor mounts and bad alignment help speed up the wear also

 

[nick97]

old age
bad oring seals (2 of them) inside the mid shaft letting water wash out spline grease
when was the last time you greased it?
bad motor mounts and bad alignment help speed up the wear also

Thanks, I've never greased it I've owned the ski for a week, not sure if the guy before me had greased it or not

 

[701TFH]

Ive had this happen before turned out the shaft had many years of riding (15+) and the teeth were worn down just enough, went riding in the surf and the prop seized from in the wear ring from it bulging inward , motor kept turning shaft stayed put and ground down the shaft and mid shaft teeth, it also cracked the shaft in half.

 

[Big Kahuna]

biggest cause is your motor being out of alignment, this causes lateral pressure on your intermediate shaft which in turn, strips out the splines. Learned this the hard way 9 years ago.....Twice in 2 weeks.