Superjet revs but barely moves

long story made longer
My kid paddles back the ski saying it’s making a funny noise and not moving. No problem you probably got something stuck in the impeller. Well not the case. You rev it up and sounds good out of the water. Put it back in the water and it revs fine but sounds like the impeller is hitting something and barely moves. I can spin the impeller shaft fairly freely and the mid shaft doesn’t spin. The cap at the coupler is about 1/4” or less. It feels as if the splines on the drive shaft and mid shaft might be slipping.
Thoughts?
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
Pull the pump and see. Leave the wear ring in the ski if you want to preserve alignment. But if your splines are stripped chances are you're gonna wanna slide the motor forward and realign the pump anyways.
 
So I can hold the main shaft by hand and rotate the coupling. It definitely sounds like it’s barely catching/slipping the splines. It actually appears the mid shaft slipped forward as there is a bit of shiny on the shaft where it goes into the bearing. It’s about 1/4 inch.
 

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Sounds like you stripped the splines on the driveshaft. You'll want to pull the engine, midshaft and pump out of the ski.@Sasquachcrap can hook you up with a new one. Typically the midshaft itself is fine but definitely check it as well. Measure the length of the shaft protruding out of back of the housing. It should be 19.5-20.5mm or .768-.807 from the tip of the shaft to the mounting base of the housing, not the rear of the seal. This will help insure proper spline engagement.
 
What would cause the splines to strip? Seems it happened all of a sudden. However my kids the only one riding lately so maybe he never noticed it. At 13 his ass could be on fire and he wouldn’t notice
 

john zigler

Vendor Account
Location
wisconsin
Typically happens from pump/drive NOT properly aligned. Be sure to replace both the drive shaft, and mid shaft. Get the tool, and do a proper pump to mid shaft alignment.
 

Big Kahuna

Administrator
Location
Tuscaloosa, AL
What would cause the splines to strip? Seems it happened all of a sudden. However my kids the only one riding lately so maybe he never noticed it. At 13 his ass could be on fire and he wouldn’t notice
Motor out of alignment is what causes the splines to strip, Dont just replace 1 and not both, Been there done that, got 15 minutes and destroyed a brand new Midshaft.
 
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