RESTO 1998 Sea-Doo exhaust pipe.

[king15012]

Okay so I have a 1998 Sea-Doo gtx with the 951 motor. The lower exhaust hose is melting, also the hose that goes from the upper pipe is melting too. The pipe a the head is cool to touch. Only the lower pipe and muffler get hot. Any ideas?

 

[tobytd]

Plugged hose or fitting?

 

[Matt Braley]

Your water regulator is shot. It's the RAVE thing on the waterbox.

 

[king15012]

Is it possible to clean it? Or Atleast verify it’s bad?

 

[Matt Braley]

If you can safely watch it during operation you will likely see it leaking. Slide the retainer off and make sure the spring is in there and not broken. Yank the inside piece out and inspect the rubber bellows for tears or cracks, make sure the clamp has not failed that keeps the bellows on the plastic piece that moves up and down.

 

[king15012]

So, I hade the ski looked at. Supposedly there was a blockage in the tune pipe? I’m not sure I’m sold on that. I know the ski wasn’t water tested. They also told me if it doesn’t fix it I need a water box?

 

[funsummerahead]

I'm not really sold on that idea either. If there was a good blockage the engine just wouldn't run at all. Check the water lines and the water regulator and clean it. Only reason to get a new water box that I can think of would be if there's a hole in it. It may need a good cleaning though. If your exhaust is all gummed up maybe the wrong oil was used so definitely check the Rave valves on the engine too and make sure they're working properly. More than likely it's the water regulator or a clogged water line to it.

 

[king15012]

I know I have water to regulator. The lines are cold to touch at the T to the regulator. The other house is just a vacuum type right? I can blow through both hoses with the regulator off. I cleaned the fitting on the water box. I did not try to blow through the bottom of the regulator.

 

[mikidymac]

No the valve lets water into the pipe and into the water box then dries out the pipe to get more RPM but keep from melting hoses.

There are 2 different water systems working on the pipe.
1. There is a water jacket that cools the portion of the pipe closest to the engine that is fed the same cooling water as the cylinders but is not mixed with the exhaust gasses.

2. The second water system is controlled by the regulator on the water box. This actually injects water into the exhaust stream in the pipe to change the sonic wave for performance basically tricking the engine into thinking the pipe is either longer or shorter depending on rpm but this water also cools the exhaust stream enough so you don't melt the rubber parts. So if the regulator is leaking or not working you will melt the hoses like Matt B said.

So first I would blow out all water lines with compressed air. Next I would inspect the water regulator for a bad clamp or torn rubber bellows. The water boxes and pipe don't go bad.

 

[king15012]

Thanks. According to the guy who worked on it. The water jacket was gummed up. I’ll pull the regulator off tonight before I do a trail run. Anyone know if a place to buy one? Used maybe. And is there a base setting to it?

 

[mikidymac]

I have never seen a pipe gummed up. I am not even sure what that means, the only thing flowing through that is water so if that was plugged with crap your cylinders would be full too.

Check your regulator first, don't just buy a used one.

 

[king15012]

So I should be looking for any rips in the diaphragm, bad clamp, and broken spring? Is there anything I shouldn’t be able to blow through?

 

[mikidymac]

No, all lines should be clear on the entire ski.

 

[king15012]

Awesome, I’ll post back as soon. As I can get it apart. I don’t want to melt another hose trying to trouble shoot.

 

[king15012]

So, all lines appear to be clear. I couldn’t find anything tears in the bellows, but it was leaking. I’m assuming that’s the issue at this point. Being that the hose coming from the regulator to the tune pipe was melting. I’m ordering a new regulator.

 

[mikidymac]

Most of the time you can replace the bellows and clamp and stop the leaking but I have seen a few that the actual housing is distorted and can't be saved. If it is leaking then it isn't doing it's job.

 

[king15012]

Most of the time you can replace the bellows and clamp and stop the leaking but I have seen a few that the actual housing is distorted and can't be saved. If it is leaking then it isn't doing it's job.

 

[king15012]

Not sure if I added that photo correctly but should the bellow be semi stiff also? And should it be that far from the bottom of the shaft?

 

[mikidymac]

It looks pretty normal. If you can't get it to seal it is probably the housing.

To reinstall you need to push it down really hard. Then lightly pull up on it and it should not come out but he bellows should extend.

 

[king15012]

I have a reman one coming, off eBay, with a new bellow. 60 bucks shipped. I’m just throwing that one in. Pulled the hose to the regulator while running and I had water but no water from the regulator. What’s the base setting for when the new one arrives?

 

[mikidymac]

Just match it to the old one and if your's had washers under the spring put them on the new one.

 

[funsummerahead]

Not sure if I added that photo correctly but should the bellow be semi stiff also? And should it be that far from the bottom of the shaft?

I haven't had one off in a while but I think it's in the wrong place. That coil spring on the bottom of the bellows should be holding it between those 2 ridges.

 

[mikidymac]

I haven't had one off in a while but I think it's in the wrong place. That coil spring on the bottom of the bellows should be holding it between those 2 ridges.


View attachment 40261

That's not correct. The bellows doesn't go in that groove.

That groove howereve has been a mystery as it looks like it should contain an o-ring to seal the piston head to the body preventing leaks. The manual and the factory all have that groove empty but some here have added an o-ring to ones that will not stop leaking with no perceived issues.

 

[king15012]

On to the next thing. I’m pretty sure the guy who worked on them was trying bypass something or messed up. The hose coming from the top of the regulator should be routed to the lower port in the tune pipe? It’s currently routed to the top port of the tune pipe. ? I’m guess it’s a good thing I haven’t ran this ski since he touched it

 

[king15012]

As far as I can remember it was opposite when I took it to be worked on. And all the diagrams I’m finding are opposite how it is currently routed.