Engine Binding After 140mm Pump Rebuild (95 GTX)

[SigEp368]

My 1995 GTX was running fine until it blew out the wear ring last week. I put in a new OEM wear ring, and verified 0.10mm clearance all the way around with proper end play. The bearings looked good an the impeller spins freely by hand in the pump housing. The problem occurs when I reinstall the pump on the drive shaft, it seems to bind up the engine before I get the pump torqued down properly. I haven't pulled the driveshaft out of the flywheel, but to my knowledge everything was put back per the book and the pump rebuild thread. I used a puller to remove the pump (i.e. no yanking), so I cant imagine the engine alignment changed during the rebuild.

Once I start pulling down to 26 ftlbs the flywheel becomes hard to move by hand (with no plugs in) and the starter struggles to turn over (even with the plugs out). When I watch the shaft spin it seem to wobble a bit, though I checked the wear ring and it isn't scarred or scratched as if it were misaligned. The only thing I can think of is that that it is that the pump is out of alignment, or the drive shaft is bent, not sure how to check either since I don't have the proper tooling. Is there an easy way to check alignment or deflection without special tools? Any ideas would be appreciated.

Please and thank you.
Rich

 

[tobytd]

Lay drive shaft on flat surface and roll.

 

[DanSquires]

the pump is squeezing when you're torquing it down. It's pretty common.

loosen bolts about 3 turns, enough that the engine will turn over and start. When idling, tighten down bolts. it'll clearance itself.

 

[SigEp368]

I still cannot get this pump to bolt up right, so I am asking more help. I ended up completely rebuilding the pump, and rented the tools from OSD to make sure everything was aligned. I torqued the impeller to specs, verified <1mm clearance all the way around, and that it spins freely in the housing by hand. To the best of my knowledge, the pump meets specifications. I even replaced the carrier bearing while I was in this far.

I verified that all shims were in place, and that there is nothing foreign inside the flywheel housing that could be blocking the the driveshaft from fully inserting. I bolted everything back up, and even when the nuts are just hand tight, the flywheel starts to get tough to spin by hand (with plugs out). I also noticed resistance at certain parts of the rotation. With nuts still hand-tightened, I used the starter and I noticed a slight wobble in the driveshaft (see video). When I torqued to specifications, the starter was barely able to crank. I did check the wear ring and there does not appear to be any rubbing, so i don't think the wear ring is capturing the impeller. I must have assembled this thing a half a dozen times, each time with the same result.

I pulled the driveshaft and rolled on flat surface, and there is a definite bend that causes it to settle predictably in the same spot each time. I can't measure the deflection, but I assume it is out of specification. Would a bend to this degree be enough to cause the binding issue I am experiencing, or is there something else that could be locking me up?

This unit was working flawlessly until a piece of the wear ring broke out and caused cavitation. There have been no modifications the engine mounts, and it was operating in deep water when it went down, so I can't think of anything that could have bent the driveshaft.

Is it more likely that the driveshaft warped on its own and caused the wear ring failure, or did I warp the drive shaft during reassembly of the pump?

I am trying to source a new driveshaft, hopefully the Rona doesn't ruin what's left of the season.

Please and Thanks,
Rich

 

[Burner71]

when was the last time you greased the carrier bearing on the shaft?

 

[POPPS]

Its possible, (I have done it temporarily),,,,that when you tightened the prop, you locked up the thrust washer....with the pump out,,,can you rotate the prop with one finger without cutting your finger?...you should not get cut,,even with a perfect blades.

 

[etemplet]

Lots of good information on the subject. I didn't read everything but I'll just mention.. If there is a rubber inside the PTO and you added another one that would create excessive thrust and cause a problem Excessive great will make it difficult to get the drive shaft mounted.

On th pump, which I believe has been mentioned. You should have about .020" end play. If you can't pull the prop in and out just a tad... you have a problem. Hang in there and good luck !!