Carbon Seal Cavitation

[KyleW2]

Well, the rain has been insane and has prevented me from riding the ski and have another full week of rain coming, so off to the forum I go instead of lake testing my theory.

Will a drive shaft being forward (due to lack of enough grease) cause a slight leak/cavitation at the carbon seal? I had my 96 GTI out today and had very slight cavitation off idle. Pulled it out and noticed a bit of water in the hull. drained water, backed back in and started it and revved it. No leak at the carbon seal anymore. Couldn’t find another leak anywhere.

Got home pulled back on the carbon seal. Seemed to move way too easily (but this is my first ski with a carbon seal). Went ahead and pumped the fitting, shaft moved about 1/4” before stopping. Carbon seal seems tighter against the carrier ring than before. Have also read about loosing the clamp, sliding bellows a little and retightening, but figured I’d try the grease first.

Could that be my issue, just not enough grease? I would go test it…but Texas weather doesn’t want me to enjoy this GTI I guess.

 

[etemplet]

You're issue is not the amount of grease. The value of the grease and purpose is to keep the PTO and Drive shaft splines lubricated. It tells you in the manual that when adding grease, as soon as the drive shaft begins to move, "stop."

If the shaft moved 1/4" I'd suspect the rubber bumpers on the drive shaft are not in place. The bumper on the PTO end helps the condition you are trying to remedy. If it isn't there you won't have enough pressure on the Water Seal. You could have an old bellows that needs to be replaced.

I'd pull the pump and have a look at everything. Maybe replace the water seal and bellows. You'll have piece of mind and the seal will work as intended. Good Luck

WATER in the hull can come from many places. Leaking steering cable, Bailers, leaking hose or fitting on the coolant system, etc... sometimes it takes a while to locate them. I dry the inside of the hull and put the ski in the water. I also ride the skis with the seat off trying to find leaks. If you ride with the seat off you'll be able to see the seal leaking but... watch where you are headed.... LOL Good Luck

 

[KyleW2]

You're issue is not the amount of grease. The value of the grease and purpose is to keep the PTO and Drive shaft splines lubricated. It tells you in the manual that when adding grease, as soon as the drive shaft begins to move, "stop."

If the shaft moved 1/4" I'd suspect the rubber bumpers on the drive shaft are not in place. The bumper on the PTO end helps the condition you are trying to remedy. If it isn't there you won't have enough pressure on the Water Seal. You could have an old bellows that needs to be replaced.

I'd pull the pump and have a look at everything. Maybe replace the water seal and bellows. You'll have piece of mind and the seal will work as intended. Good Luck

WATER in the hull can come from many places. Leaking steering cable, Bailers, leaking hose or fitting on the coolant system, etc... sometimes it takes a while to locate them. I dry the inside of the hull and put the ski in the water. I also ride the skis with the seat off trying to find leaks. If you ride with the seat off you'll be able to see the seal leaking but... watch where you are headed.... LOL Good Luck

1/4 was an exaggeration now that I think about it, more like 1/8” is more likely. I noticed a small drip from the outlet hose fitting (the one with the inline hose flush fitting) at the back of the hull, but figured I’d narrow down the cavitation first.

Rain is gonna hold off today so I’ll run out and test it again today and run it with the seat off.

 

[DaddyLoafin]

I have been dealing with the same thing. I pulled the drive shaft and the pto side bumper was chewed up pretty good. While I had it apart I checked the engine alignment and it was sitting over to the left side. And I also noticed there was no O rings between the pump and nozzle for the bailers which was probably also letting water in.

 

[etemplet]

You can remove the clip holing the mating ring and slide the it back enough to move the drive shaft forward and aft to determine if the bumpers are in place. If you can easily disloge the bellows from the mating ring by pulling it toward the back of the ski there isn't enough pressure on the seal. If it is stiff to pull back it's probably OK. Good Luck !

 

[etemplet]

I have been dealing with the same thing. I pulled the drive shaft and the pto side bumper was chewed up pretty good. While I had it apart I checked the engine alignment and it was sitting over to the left side. And I also noticed there was no O rings between the pump and nozzle for the bailers which was probably also letting water in.

Yep, sounds like the same mechanic that worked on your ski got around the GTI I'm fixing up for my cousin. LOL I had a problem with the bailers doing the same thing on 1995 GTX but only when I turned the ski hard left or right. I put the bailers in parts containers to see what was going on.... oh was that a PIA. LOL Glad your got yours straightened out !!

 

[DaddyLoafin]

Yep, sounds like the same mechanic that worked on your ski got around the GTI I'm fixing up for my cousin. LOL I had a problem with the bailers doing the same thing on 1995 GTX but only when I turned the ski hard left or right. I put the bailers in parts containers to see what was going on.... oh was that a PIA. LOL Glad your got yours straightened out !!

Haha don’t know if it’s all good yet. I still got to take it out and test it. Hopefully I can get out tonight or tomorrow and see.

Before I took it all apart to replace everything last week I took it to the ramp and ran it on the trailer to see if the bailers were flowing backwards and they seemed to be working correctly. I wonder if they were letting water in while doing turns like yours.

 

[etemplet]

When the bailers did that on the 95' GTX the ski did great in a straight line, when I'd get close to coming back I'd cut up a little bit.... there would be a lot of water in the compartment. I rode with the seat off and couldn't see where the water was coming from. I DON'T recommend pulling the sponsons.... day yum that was a pain !! So I had two containers and I put the bailers... one in each. When I turned hard the containers filled up pretty quick (they were small but about a quart each). LOL Root Cause was one of the o-rings was pinched upon install. It wasn't me, I just found the problem

 

[DaddyLoafin]

haha I bought mine I’m January and started going through it once the weather started warming up and I’ve found all sorts of sketchy stuff. A 30amp fuse in for the vts even though it wasn’t working and it being a 98 there was 3/8 and 5/16 fuel lines on it instead of 5/16 and 1/4. Lol some people.

 

[DaddyLoafin]

Sorry to thread jack you OP. But here is what my pto drive shaft bumper looked like.

also when I tested it on the trailer I could see the drive shaft move back towrd the engine when I’d rev the engine up and create a small gap between the float ring and carbine ring. Now that I’ve replaced those and the carbine ring assemble it’s nice and tight, but I’ve yet to take it out and test it.

 

[KyleW2]

No worries! More info the better.
So rode it without the seat. I can still feel the cavitation but it is not the carbon seal as water is not getting in there. Looked to be working as normal..just feels like it’s slipping off idle but doesn’t feel like a bog.

 

[KyleW2]

Okay, quick question. Would an improperly seated pump cause low speed cavitation like that?

 

[mikidymac]

Yes, anything that can let air into the pump tunnel will cause cavitation.

 

[KyleW2]

Definitely think I found my issue.
The “performance shop” who did the carbs for previous owner half azzed that job, so why am I surprised that he half azzed the wear ring also? Lol. Now if I can get this damn pump out I’ll be in good shape

 

[KyleW2]

I should also add to this thread that turning right, power seemed normal. Turning left or straight on, that's when I noticed the issue..

Anyway, painfully obvious that the shop did not replace the neoprene seal when replacing the wear ring.

This carbon seal did not leak...that I saw. Should these surfaces be perfectly smooth?

 

[mikidymac]

You found the issue for sure.
Carbon seal looks worn but I have seen worse work fine.

 

[KyleW2]

Noticed an o ring spacer behind the bellows so went ahead and ordered the replacement kit. Pushing my budget a bit on this flip but would rather it be done right. Will hold on to the old carbon seal for a rainy day. Never know!

 

[KyleW2]

Well after 2 weeks of back and forth on carbon seals from Amazon coming in bad (since OSD was closed) I decided to just pull the carbon seal off the RX and use that one. Finally got it reassembled and tested it today, man what a difference. Speedo read 50 (yes, I know they aren’t accurate).
Turns out that O ring I found is actually out there from the factory according to the parts schematic, so I left it on.

Now to just ride this GTI while I wait for it to sell.

 

[DaddyLoafin]

The carbine seal I got off Amazon was made by Titan 757 and the stainless float ring wouldn’t fit on the drive shaft with the orings on it, so I had to hone the face of the one that was on it before and reuse that.

Also got a wear ring made by them and while it looked identical to the oem one I have now it had laughable amount of tool marks all over it. Which was promptly returned lol.

 

[KyleW2]

The carbine seal I got off Amazon was made by Titan 757 and the stainless float ring wouldn’t fit on the drive shaft with the orings on it, so I had to hone the face of the one that was on it before and reuse that.

Also got a wear ring made by them and while it looked identical to the oem one I have now it had laughable amount of tool marks all over it. Which was promptly returned lol.

Yep...Same kit I ordered. Carbon ring surface was damaged when the first kit arrived. Took them 3 days to send out a replacement...replacement came in even worse with damage, completely unusable. Gave them 48 hours to reply about either a refund or checking for a GOOD carbon ring before shipping. No response. Got Amazon involved and we gave them an additional 3 days. Still no response. So last night Amazon took my side and refunded my money and told me to keep the parts. That's what I get for buying cheap parts I guess. Will buy the replacement kit for the RX from OSD when I'm ready for it.