Shims of Jet Drive

[mashenden]

I pulled the jet drive today on the "new to me" '95 XP800 to see if the pump or engine is locked up. It is the engine, as suspected.

As I removed the pump assembly, I noticed that there were shims on all 4 of the studs that hold the jet on (between the spacer and jet drive). All shims appear to be the same thickness. Why would there need to be spacers on all 4 studs? Since they are all the same thickness, it does not seem to be associated with an adjustment in alignment. And I can't see why the drive needed to be a fraction of an inch further out.

Having used an alignment tool recently to align an engine, I started to wonder how someone would even figure out what shims are needed on the pump end (as opposed to the engine mount shims).

Any ideas on why they are there? Or how one would determine if they are needed? Or if more are needed on some but not all of the studs?

 

[mikidymac]

The pump shims are installed from the factory and should always stay where they put them. The factory must have had a way to align the pump to the hull then the engine to the pump. The best rule would be to just leave them.

 

[mashenden]

The pump shims are installed from the factory and should always stay where they put them. The factory must have had a way to align the pump to the hull then the engine to the pump. The best rule would be to just leave them.

That was how I was leaning too.

Do you know if I bolt the alignment tool to the extender, and leave the jet pump shims in place as well, when re-installing the engine?

Also is it common to have shims on all 4 studs on the jet pump?

 

[racerxxx]

I pulled the jet drive today on the "new to me" '95 XP800 to see if the pump or engine is locked up. It is the engine, as suspected.

As I removed the pump assembly, I noticed that there were shims on all 4 of the studs that hold the jet on (between the spacer and jet drive).

There are no shims between a pump and a pump extension. POSSIBLY between the pump extension and the hull. But not between the two surfaces. The bailer lines and the water in line from the pump have to be sealed, hence the RTV and o-rings on a factory pump to hull set-up. If you shim it you break the seal. Now #42 is a shim, my 95XP800 doesn't have that(I can't see one in there) and it still has the original goop on it. Mash post some pics of the shims. on the pump nuts are there flat washers and lock washers?

Here is the pump extension set up, you can see #26 O-rings for the bailers, then the RTV for the water in line.
http://fiche.seadoowarehouse.com/se...=220&b=19&c=0&d=-PROPULSION-SYSTEM---EXTERNAL

 

[mashenden]

There are no shims between a pump and a pump extension. POSSIBLY between the pump extension and the hull. But not between the two surfaces. The bailer lines and the water in line from the pump have to be sealed, hence the RTV and o-rings on a factory pump to hull set-up. If you shim it you break the seal. Now #42 is a shim, my 95XP800 doesn't have that (I can't see one in there) and it still has the original goop on it. Mash post some pics of the shims. on the pump nuts are there flat washers and lock washers?...

These were between the pump and pump extension, not between the extension and the hull. They were thin enough to not cause the seals to leak (presumably) but you make a good point that they would oppose what the o-rings are supposed to accomplish. Very odd.

Yes, there are washers and lock washers with the nuts, but the shims are much thinner, and much larger diameter (similar to the engine mount shims, but without the tab).

I wonder if the PO pulled the pump then put the shims back in the wrong place??

 

[suke]

Weird, mine had something similar but it was between the hull and the pump.