1998 GTXL Cavitations. Help please

[sledman1]

Boy could I use some help from the resident Jetpump experts. This is going to be a bit long but I want to give you all the information I have. Bought a 98 GTXL with a blown motor and 300 hours on it. So I rebuilt the motor and also rebuilt the jetpump since it had so many hours and I did not know the maintenance history on the ski.

On the pump I replaced all the bearings and seals a long with the shaft. One of the bearings had spun and the diameter of the shaft was just out of tolerance. Replaced the wear ring as well. The impeller was a little beat up but we cleaned it up a bit and used it.

When I first put the ski in the water it was working pretty good with just a little cavitations. The amount of cavitations seems to get worst and it got to the point where I had to get to 20 MPH before the cavitations would stop and the ski would take off.

I replaced the intake crate with a Solas unit and pulled the pump and installed a Solas Concord impeller. Took it out on the lake yesterday and it seems even worst then before the intake and impeller replacement.

This year and model jetski was built with two different drive configurations depending on when it was built. At one point I was reading on the forums about the carbon seal and using the bellows to apply pre-load the carbon seal. I figured this was my problem and purchased some heavy duty tie wraps to try that little trick to stiffen up the bellows. When I got home I realized that my drive setup was different and that I did not have a bellows. My ski has a thick rubber hose about 4 inches long with clamps on both ends. So no Carbon seal but a couple of regular seals on the driveshaft inside the ski. These seals are the only thing I can think of at this point to blame my problem on.

One last note, I did not use an alignment tool when I installed the engine back into the ski after the rebuild. Summer is running out and I would like to get this thing set before the snow flies. Any suggests would so greatly be appreciated.

Thanks, Don

 

[Dr Honda]

If your alignment is close... you are fine... if it's out... then you could bend the driveshaft. (or wear the splines out of the impeller or PTO)

As far as your cavitation... that's an air leak. Most likely, around the carbon seal. So... replace all of it, and you will be fine. OR... if your drive shaft has 2 spots for the clip... you can compress the boot, and put the clip in the next spot.

 

[sledman1]

No carbon seal or bellows/boot on this ski. See file attached for the drive configuration on my jetski. They used two different setups on this model and year. One uses a carbon seal/ bellows and the other does not.

 

[sledman1]

Another item that might help solve this is that this particular unit does not use a neoprene seal. The service manual shows a neoprene seal but the parts microfic does not. Verified with the dealer that no neoprene seal is used on this ski. Just use the Ultra black RTV between the jetpump and the hull

 

[Dr Honda]

Regardless... you have an air leak. If you have the seal pack, rebuild it.

 

[LouDoo]

Also, I would use a neoprene seal anyway, Chester says to use a neoprene seal, that's good enough for me. My 96GSX is very similar to your pump and ride plate and I use a neoprene seal.

Lou

 

[sledman1]

Thanks so much for your input. I will do as you suggest and replace the two seals that are on the driveshaft inside the ski and install a neoprene seal. Also load it up with lots of grease. I think the owner of my local Seadoo dealer mentioned that he has doubled up on the neoprene seal on some skis that were stubborn when it came to cavitation. I think I will talk with him about that.

Pulling this pump and install it again is pretty easy but it is getting old. Looking forward to the day when this jetski starts out of the hole like it should. Thanks again!!

 

[sledman1]

Well I went to my local Seadoo dealer to pick up the seals. I grabbed the owner to discuss the idea of installing one or two of the neoprene seals. He stated that I have done all the right things and he does not believe the shaft seals or the Neoprene seal is the issue. He believes that the shoe and pump support need to be removed and resealed with RTV. This guy has been doing this for a long time so I decided to give this a try. Any thoughts on this?

 

[LouDoo]

Thanks so much for your input. I will do as you suggest and replace the two seals that are on the driveshaft inside the ski and install a neoprene seal. Also load it up with lots of grease. I think the owner of my local Seadoo dealer mentioned that he has doubled up on the neoprene seal on some skis that were stubborn when it came to cavitation. I think I will talk with him about that.

Pulling this pump and install it again is pretty easy but it is getting old. Looking forward to the day when this jetski starts out of the hole like it should. Thanks again!!

Load what up with grease???? You pump takes 75w90 GL5 oil not grease.

Lou

 

[sledman1]

I was refering to putting grease in the grease fitting that is on the driveshaft between the thru hull fitting and the engine coupling inside the jetski. Thought that might help stop any air that is being sucked in thru that path

 

[Dr Honda]

Loading the grease in the seal is a band-aid. Yes... the bearing needs grease, but the grease isn't your "seal."


Removing the shoe is a pain in the a$$. I only recommend it as a last resort. There is a member in the boat section who decided to remove it... and it ended with a shoe that was in about 6 pieces on the ground. AND... since you can't buy them anymore... he had to find someone parting out a boat to get one. AND... since they are a pain to remove... they dont' normally show up on ebay. (they get sold/trashed with the hull)

Think about it... the seal pack is a wear point. It needs rebuilt every few years to perform as it should... and to stay safe. Also... if the pump was off, and you didn't replace your wear ring (the plastic lip of the ring is your seal)... then you don't have a true seal between the pump and the shoe. The neoprene gasket will crush down to nothing if need be... and it will seal the pump.


Do what you want... but unless you can find some physical damage to the shoe (from the bottom) then I doubt the factory RTV is leaking.

 

[sledman1]

Pulled the Shoe and pump support last night. Managed to do it without breaking it. It was a pain. When I look at the diagram for the drive setup on my ski it looks like there are two seals in the seal carrier. I will replace these as well while I am at it. It looks like that is all the seals the inside of the ski from the outside of the hull where the driveshaft goes out. Does anyone know if you have to push the motor forward to get the seal carrier out? Remember I do not have the carbon seal/bellow setup. Thanks Dr. Honda and LouDoo for your help.

 

[Dr Honda]

Once the drive shaft is out... just loosen the clamp, and the seal pack will come out.

 

[sledman1]

Re-sealed the shoe and pump support, installed neoprene gasket where I have used "Ultra Black" RTV before and rebuilt the seal pack. I will try it out tomorrow and let you know how I made out. Got my fingers and toes crossed

 

[sledman1]

No more cavitation!! Don't know which of the things I did fixed it but at least it's done. Was enjoying it until my buddy sucked up the anchor line and wrapped it around the drive shaft about 40 times. It was fun getting that out. Thanks again for your help.