jet pump bearings, now i can't spin the impeller

[kmarts]

So I got all new bearings for my jet pump from OSD and pressed them in. I put the impeller back on and torqued to 52 lbf as per the manual. But after doing that I can't spin the impeller by hand. Is that normal? Before i rebuilt it and the jet pump on the ski i was able to turn the engine by hand (with the plugs out), using the drive shaft.

I don't know if I'm paranoid or if i did something wrong.

 

[kmarts]

so i put the spline tool in the impeller shaft and rotated it with a ratchet while the pump housing was in a vise. There was initial resistance, then there was a light 'click' and now it seems to turn normally.

At this point I'm just wondering if this is normal and i should re-install, or if i mucked something up and shouldn't.

Any advice appreciated.

 

[JeremyD615]

It’s possible that you pinched the thrust washer when reassembling it. I’d pull the impeller back off and check it over.

 

[racerxxx]

Did you make sure the heavy washer want pinching the thrust beating? You should be able to put the 2 flats on the impeller shaft in the vise and lift up and down on the pump housing and it should move

 

[AKnarrowback]

It's very common to pinch the thrust bearing/washer when putting a pump together if you do not know to watch out for it. If it's pinched it won't spin.

 

[kmarts]

pardon my ignorance but what is a 'pinched' thrust bearing? I've read this term a couple times but don't understand how it happens. The thrust bearing is between two flat surfaces and is itself essentially flat (aside from the bearings obviously). I'm assuming that's what happened, i just don't get how.

 

[AKnarrowback]

When you are putting the impeller shaft into the pump the thrust bearing needs to be aligned so the shaft is seated inside the bearing before you tighten the impeller down. You can drop the shaft into the pump thinking everything is seated when in fact the bearing is caught in the groove near the end of the shaft. As you tighten the impeller the bearing is squished by the groove and this locks the pump.

When putting things together you put the shaft in with the bearing then spin things by hand to make sure the bearing is seated then, holding the shaft into the pump, you spin the impeller on by hand. Once the threads bottom out you spin things by hand to make sure the bearing is safe then you tighten the impeller.

 

[kmarts]

ok that makes sense, thank you!

 

[kmarts]

So... As i had said, when i spun it with a ratchet there was a click. Since it spun fine after that i didn't think anything of it, put it back in the ski last night but when i tried to spin the engine by hand via the driveshaft it wouldn't move.

I took the pump apart again and i found the thrust washer in about 5 pieces. The click must have been the washer snapping...



When reading about a pinched washer i now realize I was thinking of the thrust bearing being 'pinched'. not the washer. I don't know why my brain was making that association but it's pretty clear how that happens.