97 XP Shredded Driveshaft Damper

[thomas0202]

Finally got the chance to water test my 97 XP now that I've put a motor in it. Other than a little tuning of the carbs it ran fantastic. Go to add oil this morning and notice red flakes all around the engine. Look down and see the damper between the PTO and driveshaft is essentially gone and theres bits of it laying in the bottom of the hull... Ski never had any vibrations or noises when riding yesterday. The PTO was a little beat up when I put this engine back together but it did not seem too bad so I went with it considering I could not find a new one at the time. I did align the motor when I installed it and I've pulled and pushed on the engine and it does not move so I don't think I have a broken engine mount. Could the PTO having been gored up in the past have caused the dampener to shred that fast? I'm attaching some pictures of what it looks like after I pulled it apart this morning. I assume I need a new PTO and driveshaft at this point... Is it possible to pull this PTO with the motor in the ski? I really don't want to go through taking this motor back apart and reinstalling it again if I really don't have to.

 

[JJinSC]

This happened to mine last year. It most likely was not caused by anything other than age on the coupler dampers. They get dry and brittle around this age and once they start breaking apart, they disintegrate fast. Your couplers are dinged, but they are not that bad considering the purpose of the dampers and nylon bushings. Order two new dampers and center nylon bushings if needed and put it back together. If it’s good and snug, I’d says it’s probably ok. In that last picture the one nylon bushings looks fine.

 

[thomas0202]

This happened to mine last year. It most likely was not caused by anything other than age on the coupler dampers. They get dry and brittle around this age and once they start breaking apart, they disintegrate fast. Your couplers are dinged, but they are not that bad considering the purpose of the dampers and nylon bushings. Order two new dampers and center nylon bushings if needed and put it back together. If it’s good and snug, I’d says it’s probably ok. In that last picture the one nylon bushings looks fine.

The damper that got shredded was actually a brand new one... I put new ones in because when the motor blew and I pulled it I noticed the old ones were nicked and coming apart. I have a spare damper and I threw it in and this is what it looks like. There’s definitely some play in that joint. I can rock it really any direction and you can hear and see it moving around. I’d imagine it’s supposed to be pretty tight and not rock around at all. The rear joint is solid with no movement.

 

[JJinSC]

Yeah, there should be no movement. Is the nylon bushing alright in that joint?

 

[thomas0202]

It looks to be okay. No real visible cracking or anything like that. The joint just is sloppy side to side and up and down. Like you can grab it and it’ll move any way you pull or push it and clunks some. I realize I forgot to upload the picture of the joint back together. You can see the gaps between the damper and the couplers

 

[JJinSC]

Yeah, if there is that much play that is going to be an issue and that last picture with it together is kinda telling.

 

[thomas0202]

That's what I figured. I ordered a new PTO, driveshaft, and damper. Trying to find a new nylon bushing too

 

[JJinSC]

Lets us know how it turns out.

 

[thomas0202]

Got the PTO in today. How am I supposed to get the old one off with the motor in this ski? Clearly it doesn’t matter if I gore the coupler anymore so I’m open to whatever. I’ve tried with a big pipe wrench for the past hour and couldn’t get it to budge. There’s just no room to get any leverage where it’s positioned in the ski

 

[thomas0202]

Update on the ski. Got the new PTO, driveshaft, and dampers in. Aligned the motor with the tool and took it out and it shredded the new dampener again in 5 minutes. I can’t begin to figure out what it might be. Am I off on the alignment? The tool gets really close to sliding in perfect without the carrier bearing in and with the carrier it slides in butter smooth. What am I missing here? The motor mounts all seem solid too. I can torque any which way on the motor from the exhaust and it doesn’t move at all

 

[JJinSC]

If alignment is all good, the only other thing I can think of that might cause this is play front to rear. Have you checked for play in that direction on the shaft?

 

[thomas0202]

With the old parts there was some front to back play but I didn’t notice any with the new ones. I’ll take it apart and put it back together with my spare dampener and see what I have for play. If I do have play in that direction where would I pickup that slack at? The rubber bumper is in the shaft end that goes into the impeller. Another thought I had was could my motor mounts not be broken but weak enough that under torque they collapse some and allow the motor to twist too much?

 

[thomas0202]

Another update. Found out I had about a 1/4 inch of front to rear play in the driveshaft. Read somewhere that putting some shims in the impeller to take up that slack. Shimmed it to where I had just a slight bit of back and forth. I mean like 1.5 mm or so play. Took it out and rode for a few minutes. Came back and the coupler was actually still in one piece. Every other ear was bulging out and starting to wear away, but it was still there. Not much play either. Rode another 45 minutes or so and stopped and it’s missing one ear and it’s beginning to really shred now. This was an older rubber coupler, but I’m still convinced I’ve got something wrong. How much front to back play should there realistically be? Also could the midbearing wearing out play a part in this? The seals on it are questionable, but it doesn’t have any play in it. I’m attaching a picture of the coupler after the first check to show you what I mean and then another after the long ride.

 

[JJinSC]

That second picture looks like it is melting. See the stringy pieces coming off of it? I wonder if your PTO is getting too hot somehow. Is that the only one coming apart or is the one at the carrier coming apart too?

 

[mikidymac]

Either your engine alignment is not correct ore the carrier bearing on the driveshaft support is bad.

 

[thomas0202]

I will say the PTO is really hot when I reach to check the play in the joint. The dampener at the carrier side is perfectly fine. The head/cylinders aren't nearly as hot. What would make it heat up that much? I can't even begin to think of a reason myself.

As for alignment and the carrier bearing, with the bearing in place, the tool slides in perfectly. The only resistance really comes from sliding the tool through the bearing. The bearing slings grease out the back of it everytime I ride so I was thinking about grabbing a new one anyways.

 

[JJinSC]

I’ll have to let the guys more experienced in the crank case of these engines jump in on this, but I wonder if your crank bearing at the PTO is shot. I would not think the P.TO should get that hot and as that is now the only one that keeps disintegrating and it looks melted to me, plus you confirmed alignment. I’m really suspect something is getting too hot at the PTO.

When you replaced the PTO coupler, was everything torque down appropriately? The correct thread lock used, etc. You don’t want the PTO being loose.

 

[thomas0202]

Yeah its definitely getting hot. And yeah I torqued the PTO down and used the correct thread lock on it.