Neoprene seal or RTV

[Goddo]

Last year my Seadoo (95 GTX) suffered from lag out of the hole due to a missing Neoprene seal between the pump and ride shoe. I purchased and installed the seal and it was noticeably better, though still not 100% in my opinion. This year after only a few trips out to the lake, I noticed that the Seadoo was slow out of the hole again. I decided to pull the pump again and take a look. I figured maybe it was the impeller and wear ring clearance. I discovered that the seal was pretty much toast again. Most of the upper half was missing and the bottom half was squat up and flattened.

I'm surprised that the seal went with less than 10 hours of use. Only thing I can think of is that I over torqued the pump when I put it on and squat the seal.

This time instead of replacing the Neoprene seal I used RTV. I haven't tried it yet, but do you think the RTV does as good a job as the Neoprene seal? Will it be more durable?
The newer pumps don't use the seal, so do people just use RTV?

Anyone have any experience with this?

 

[Goddo]

BUMP...

Does anyone know if the RTV seals as well as the Neoprene?

I'll post my findings tomorrow, but in the meantime I was hoping someone had experience with this.

 

[timmyboy76]

i'd use the neiprene, but still need to silicone the "fitting" thru the hull.

 

[Goddo]

The results are in....The RTV did not do the trick. Cavitation was terrible.

Got a new seal today and will test tomorrow.

 

[Chester]

Something else is causing the cavitation then. Silicone was used until 94. In 95, the neoprene seal was made available to replace the silicone.

Chester

 

[Goddo]

Hey Chester,

You are correct. I think the silicone could have worked, but you would have to use a lot. I thought I had used a lot but when I pulled the pump I noticed how much the silicone had shrunk when it set up.

Through this whole process I have realized the err of my ways. When installing the pump in the past I would lower the ride shoe enough to get the pump out (over the speed sensor). I would torque the pump and then tighten the shoe. However, by doing this I was pushing the shoe up (with the screws) after the pump was already tight and basically pulling or tearing the seal/silicone in the process. This time I put the pump in place, tightened the shoe, then torqued the pump so it went straight in. I haven't tested it yet, but I could tell it sealed better and the shoe went on much easier not having to push up on a tightened pump.

 

[Chester]

OK, now I understand. Never loosen the shoe to remove or install the pump. You must only remove the speed sensor. Now you have to completely remove the shoe and reseal it with RTV. Otherwise it will always cavitate. Make sure you use lots of RTV so that it squeezes out as you install the shoe. Then wipe off the excess. Also, meka sure the shoe isn't cracked.

Chester

 

[Chester]

OK, now I understand. Never loosen the shoe to remove or install the pump. You must only remove the speed sensor. Now you have to completely remove the shoe and reseal it with RTV. Otherwise it will always cavitate. Make sure you use lots of RTV so that it squeezes out as you install the shoe. Then wipe off the excess. Also, make sure the shoe isn't cracked.

Chester

 

[scooper77515]

Chester's response must be IMPORTANT!!! He even posted it TWICE!!!

I do like timmy, use the neoprene and RTV, but less RTV. It is a mess to clean up later and glues it all together making it a hassle to get into it next time.

 

[Goddo]

OK, now I understand. Never loosen the shoe to remove or install the pump. You must only remove the speed sensor. Now you have to completely remove the shoe and reseal it with RTV. Otherwise it will always cavitate. Make sure you use lots of RTV so that it squeezes out as you install the shoe. Then wipe off the excess. Also, meka sure the shoe isn't cracked.

Chester

That makes sense Chester. I read the manual wrong the first time and have been lowering or removing the ride shoe completely most times. In my case, the speed sensor screws wouldn't come out, but I'm sure that can be remedied.

The good news is that I have it in, sealed, and tested her last night with great success. Runs like new again.

Thanks.