Question regarding the temp trick to increase pressure on Carbon Seal

[Dadasaurus]

Hi all, Tomorrow we will be taking the boat (96 Speedster) out for our one and only ride this year. We just purchased it, and when we test drove it there was some low speed cavitation. Basically after slowly pulling away from the launch when you first give it throttle you hear the cavitation sound and the RPM's go up but the speed does not increase that much and the bow stays up high. Then after about 10 seconds of giving it more throttle all of a sudden the cavitation noise goes away, the bow drops and the boat takes off like a bullet. I've taken a look at the impellers and wear rings through the water inlet, and they seem to look okay to me (but I am very new to this). I was hoping to get good pics and post later to get others opinions. Also, the wear rings were replaced by previous owner a couple years ago, and the impellers were serviced at the same time (though I know it's what they have been through that's important, not time). Anyways, after reading many posts on the forum it seemed like I might have worn out Carbon Rings. When I grab the Ring's/Boot's I can easily move them around. I am hoping to change the Carbon Rings this Fall and get a better look at the wear rings and impellers then and do what's needed to them as well. Yeah, I've been doing a lot of reading on here and the Shop Manual. This is all completely new to me, but I love to work, have no problem getting my hands dirty, and I really want to learn.

Anyways, I was able to get a couple C-clips at my local Sea-Doo shop and I replaced the Floating (Stainless) Ring O-rings when I had a thought. I've read a post from Dr. Honda (I learned very quickly to pay very close attention to everything he posts!) about the temporary fix/trick where if your drive shaft has more then 1 groove for the C-clip then you can increase the pressure between the Floating Ring and the Carbon Ring by using one of the closer (to the Carbon Ring) grooves. Unfortunately my Speedster only has the one location, but I had a thought. Is there any reason why I could not push the Floating Ring toward the Carbon Ring far enough that I could move the O-ring out of the groove (toward the Carbon Ring) and then install the C-clip into the groove behind it. I figured this would give me a little more pressure between the Floating Ring and Carbon Ring.

Does my idea make sense, and do you think it's okay to do? Again, this is just a temporary fix, and is as much to serve as a test to see if the cavitation seems any better (which if I'm actually starting to understand some of all this, may indicate that indeed my Carbon Rings are worn out).

Thanks!!!

 

[mikidymac]

It is the groove on the stainless hat that holds the top of the o-ring/clip into the groove int the driveshaft. Without it being contained by the hat it could pop out of the driveshaft groove then your boat sinks from the stainless hat sliding towards the engine and water pouring in.

Bad idea.

 

[Dadasaurus]

Thank for replying! It took me as couple minutes to process what you said, but now I think I have it. The Stainless Hat sitting over the C-clip keeps it from being able to pop off. That is exactly why I posted the question, I just learned a little more. Thank you very much!

 

[mikidymac]

You are correct, the hat retains the clip.

 

[racerxxx]

Pump grease into the zerk fitting on the pto. That will push the driveshaft back towards the pump, which in turn puts pressure on the stainless hat and carbon ring, creating a better deal with more pressure. I'll bet 75% of people never put grease in there. All you need to do is pump it up until the driveshaft JUST stops moving backwards. I use Mobil 1 synthetic wheel bearing grease, it's red. Make sure you don't over fill it and rupture the rubber boot on the pto.

 

[racerxxx]

Also, depending on how big your guests are, send the largest one up to the bow to transfer the weight. Then once on plane they can come back.

 

[Dadasaurus]

Thanks for the replies Racerxxx! I read about the pto zerk in the shop manual, I'll fill that in the morning before we head out.

 

[nisjeep]

Undo the jubilee clip on the bellows and slide the bellows towards the hat and install a zip.tie behind it so it applies a bit more pressure. Tighten down jubilee.

 

[Dadasaurus]

Thanks nisjeep I really do appreciate your reply, but unfortunately I have bigger problems to worry about now. Blew a hole in my tuned pipe on my maiden voyage this weekend.

 

[nisjeep]

Thanks nisjeep I really do appreciate your reply, but unfortunately I have bigger problems to worry about now. Blew a hole in my tuned pipe on my maiden voyage this weekend.

Good luck with that Mate. Down here we fix it with Plastic Steel and then have it welded after the weekend is done !

 

[racerxxx]

Did you have a Welch plug rot out? I make them.
They're $5 each plus $7 to ship for however many you need as long as they fit into a small usps flat rate box.


Seadoo 720/787 Welch plugs, Exhaust plug/cap or whatever you want to call them.......