So what exactly does the intermediate bearing do?

227

Its all about the surf!
Location
Oceanside, CA
After losing my second one in so many months I’m questioning Yamahas design.

The obvious answer is for additional support of the drive line, but my Kawasaki doesn’t have one. AND you don’t need to shim a Kawasaki motor like a Yamaha either. So I guess my question is WHY does the Yamaha design use an intermediate bearing AND require motor shimming and the Kawasaki design doesn’t require either?
 

Big Kahuna

Administrator
Location
Tuscaloosa, AL
The kawi is a floating style drive line. The shaft goes from the pump/prop straight to the couplers. The yamaha using the intermediate shaft as a coupling. As everybody keeps saying, you have to have everything aligned properly or this will keep happening, happened to me also.
 

227

Its all about the surf!
Location
Oceanside, CA
Your Kawi does have one (it's just different) and the motor should be shimmed.

On my 750 sxi the drive shaft went right from the impeller on the pump to the coupler on the engine passing through a water seal in the bulkhead. Was the bearings in the waterseal? If so how was that helping since the drive shaft ran from the motor to the pump? I was the first owner of the ski and it had NO shims on any of the engine mounts and I never added any on any of the ten times I had to pull the motor to replace broken mounts. Did I just have a "Good" one that didn't need shimming?
 

227

Its all about the surf!
Location
Oceanside, CA
I'd bet not. I'd bet it just a matter of time.

I don't have that ski anymore but I do have an SXR (which I've never had apart yet) That appears to have the same set up. As for my Super Jet, so if the alignment isn't dead on, the intermediate bearing takes the abuse and fails prematurely?
 

Crab

thanks darin...noswad!
Location
Seattle
On my 750 sxi the drive shaft went right from the impeller on the pump to the coupler on the engine passing through a water seal in the bulkhead. Was the bearings in the waterseal? If so how was that helping since the drive shaft ran from the motor to the pump? I was the first owner of the ski and it had NO shims on any of the engine mounts and I never added any on any of the ten times I had to pull the motor to replace broken mounts. Did I just have a "Good" one that didn't need shimming?
Sometimes you can get away with that, the bearing housing can move up and down a bit if you loosen it up. I always unbolt it when installing the motor and shim the bedplate so the bearing housing is about in the middle of its travel. Bolt the engine down first then the housing last, then there is no bind on the housing at all.
 
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