99 gsx 787 rfi. I thrust

[Chr1sfrench]

99 gsx 787 rfi. No thrust

Ok guys. I went out today and the machine rode great for about 30 mins then I had no thrust. The engine was running flawlessly and would rev up and everything but I would not move faster than idle speed. I got back to the dock and there was about 4 or 5 inches of water in the hull. My wear ring is brand new and there's barely a gap at all between he impeller and it. I pulled my whole pump off and drive shaft to inspect my carbon seal. Everything looks good but I'm thinking my carbon seals bad. Any advice?

 

[Coastiejoe]

You may have something in the impeller that fell out when you pulled the ski out of the water.

Put it back together and see if it is still an issue. If so, loosen the CS boot on the hull side, move it closer toward the CS. Then put a zip tie in the space you created behind the boot to stop it from sliding back. This will out additional pressure on the CS. Then retest. If the problem is solved, you need a new boot for sure as it is weak. But I'd replace it all.

 

[Chr1sfrench]

Ok. I was thinking about trying the zip tie trick or welding a washer on this fitting to make it thicker

 

[wfo speedracer]

How did you seal the pump to the hull. I am not seeing any trace of silicone in those pics, it needs to be siliconed to the hull

 

[Chr1sfrench]

I cleaned the silicon off already before I took that pic. It was sealed on.

 

[manolocross]

How did you seal the pump to the hull. I am not seeing any trace of silicone in those pics, it needs to be siliconed to the hull

On a gsx...the pump is NOT siliconed to hull. That is on x4 hulls.
That carbon seal and ring is shot. It has to be like glass to work properly. I'm betting that boot needs replacement also....cheap easy fix. You won't beleive how well these machines run when there is no cavitation!

 

[Chr1sfrench]

I didn't think it needed to be siliconed on but I always put a little bit on. Doesn't hurt. It's hard to believe the wear ring is bad. Almost no gap and it was new when I got the machine. But idk what brand it is. So it is a possibility I guess. I'll order a carbon ring and boot for sure but I think I'm going to try the zip tie trick and see if that helps until parts arrive.

 

[mikidymac]

Also make sure the little rubber bumpers on both ends of the driveshaft are in good condition. They help position it and keep tension on the carbon ring.

 

[wfo speedracer]

On a gsx...the pump is NOT siliconed to hull. That is on x4 hulls.
That carbon seal and ring is shot. It has to be like glass to work properly. I'm betting that boot needs replacement also....cheap easy fix. You won't beleive how well these machines run when there is no cavitation!

Sorry But you are wrong here, if it was a GSX ltd it wouldn't be siliconed they have a SEPARATE rubber seal. 96,97,98 and RFI models use the 140 pump and it does need to be siliconed to the hull or use a neoprene sealing ring even though it did not leave the factory that way !

 

[mikidymac]

Although with a brand new OEM wear ring with the little lip seal molded into it they seal fine with nothing in my experience. Aftermarket or old wear rings I use the neoprene seal. So much cleaner than silicone.

 

[wfo speedracer]

Although with a brand new OEM wear ring with the little lip seal molded into it they seal fine with nothing in my experience. Aftermarket or old wear rings I use the neoprene seal. So much cleaner than silicone.

My experience has been that the ride shoes tend to warp over time, when that happens the OEM folded seal is no loner adequate to prevent cavitation, so much easier for me either silicone it in or peel and stick a neoprene sealing ring than have to do the job twice, but hey whadda I know.

I will tell what I know , I know that GSX's came with carbed and fuel injected 787 engine as well as carbed 951's, that's what I know.

 

[Chr1sfrench]

Mine is a 99 787 rfi

 

[wfo speedracer]

Hmmmmm ok I will play along

 

[Chr1sfrench]

So guys , I also found out that the little rubber bumper was missing on the pto side of my driveshaft. So that doesn't help

 

[Leon xpdoo]

I put my carbon ring in a lathe and machined off the face. Seals perfect now

 

[manolocross]

Sorry But you are wrong here, if it was a GSX ltd it wouldn't be siliconed they have a SEPARATE rubber seal. 96,97,98 and RFI models use the 140 pump and it does need to be siliconed to the hull or use a neoprene sealing ring even though it did not leave the factory that way !

I use a neoprene seal but
No silicone....
So what your saying is the manual is wrong???( for the 140mm pump)
I'm sorry but in the gsx limited 150 pump the MANUAL calls for silicone on pump with that oring...
"The right stuff" from permatex I believe...

 

[wfo speedracer]

I use a neoprene seal but
No silicone....
So what your saying is the manual is wrong???( for the 140mm pump)
I'm sorry but in the gsx limited 150 pump the MANUAL calls for silicone on pump with that oring...
"The right stuff" from permatex I believe...

I am not sure what your manual says but mine says this :

INSTALLATION
JET PUMP HOUSING
Generously apply synthetic grease on driveshaft
splines.
Make sure rubber damper is on driveshaft end.
Install jet pump. If necessary, wiggle the pump to
engage driveshaft splines in impeller.

No mention of silicone or right stuff, also it does not show up on the parts fiche either, on the parts fiche if a special lube or sealant is needed it is indicated with a part number.

 

[manolocross]

I am not sure what your manual says but mine says this :

INSTALLATION
JET PUMP HOUSING
Generously apply synthetic grease on driveshaft
splines.
Make sure rubber damper is on driveshaft end.
Install jet pump. If necessary, wiggle the pump to
engage driveshaft splines in impeller.

No mention of silicone or right stuff, also it does not show up on the parts fiche either, on the parts fiche if a special lube or sealant is needed it is indicated with a part number.

Is that what your manual looks like???
Because this is what the manual that I see looks like...

 

[manolocross]

#31
Check it out
Seadoo manual
1998 gsx limited 155 pump
Boo yah

 

[wfo speedracer]

#31
Check it out
Seadoo manual
1998 gsx limited 155 pump
Boo yah

You know I hate calling out people in public but in this case you have it coming. That is the pump support they are saying to install with right stuff Dilbert , notice the arrow going to the pump support , yeah thats a pump support, the quote I gave you is from the Factory service manual, you know the manual you refer to when servicing your Seadoo, yeah that manual !

One more thing this post is about a GSX RFI which uses (GASP) a 140 mm pump, it is a large hub pump but it is still 140mm !

 

[manolocross]

I know it says to use it for the pump Suppourt but I diagram it calls for it on suppourt to jet pump. The discussion we seem to be havin here is about if you should silicone or not...
my point was that on a 787 powered gsx with 140mm pump should NOT need to be siliconed. That was it. If you silicone it the next time the pump would need maintenance it would be a bear to come out.

 

[wfo speedracer]

I have already explained this one time, that is enough for most people here , what I posted up isn't in a service manual anywhere it was learned from the experience gained from working on Seadoos since 1990.

You clearly are here to argue and you want so badly to be right, I am not biting good day !

 

[mikidymac]

You two realize you are arguing over the exact same point? Regardless of what the manual says you are both using the neoprene seal.
Shake hands and agree to agree. [emoji106]