96 XP blowing exhaust hoses

[M24per]

Hello guys, first post so please bare with me haha.

So I bought a 96 XP about a month ago. PO said he rebuilt the carbs and got new pistons in it. Right out of the gate the ski ran fine, in my opinion, then again I am new to two-strokes so maybe I’m missing something? After looking further into it I noticed the ski was missing a flame arrestor “grill” I ordered a new one and placed it into the air box along with a new air box cover and latches. After a couple times of riding after said repairs I started to notice that the exhaust hose from cone into water box melted a hole into it. I read up on the forums and noticed people kept mentioning the WRV, so I replaced that with a whole new assembly, including replacing the wire clip for the bellow with a ziptie, and of course added a new OEM exhaust hose. Took the ski out for another test and sure enough the hose started to bubble again… I unplugged the top hose from the WRV going to the caled’ fitting in the tuned pipe while the ski was on and it was shooting water out and the pisser is shooting out fine while idling and cruising, both the engine block and top side of tuned pipe are cool to the touch but the water box and cone are scorching hot… I checked all cooling lines for blockages and none were found, I also checked the calibrated fitting going into the tuned pipe from the WRV and it seemed fine? I blew into it and got some resistance but I’m guessing it’s because the caled’ fitting has a smaller opening than the others? I ordered a new one just to make sure along with the proper loc-tite. Correct me if I’m wrong… Anyway, I’m completely at a loss and wanted to get some opinions from people who have WAY more experience than me.

 

[hingstin]

is this an 951?
here how hoses are "wired"

and flow, can it be something wit the "regulator, it should "move" at higher speeds and let more water into muffler..
check that you have flow according to picture, whats is "missing" in pic is that when valve opens it will inject water in to muffler ( my red arrow)

 

[M24per]

Sorry I should’ve clarified, this is a 787 96 XP. So I tested the WRV by undoing the top hose going into the tuned pipe while idling on the lake and it is getting constant flow out of the valve.I also took apart the valve and all parts are in it including the washer and bolt, the baffle has no holes in it. I just don’t understand why I’m still overheating the cone and exhaust hose…

Thanks for the reply!

 

[M24per]

is this an 951?
here how hoses are "wired"

and flow, can it be something wit the "regulator, it should "move" at higher speeds and let more water into muffler..
check that you have flow according to picture, whats is "missing" in pic is that when valve opens it will inject water in to muffler ( my red arrow)View attachment 68216View attachment 68214

I also looked thru the cooling diagram of the 787 and it’s actually pretty similar to this one. All lines were checked for obstructions and none were found, again I’m at a complete loss at this point haha

 

[mikidymac]

The water valve closes at higher speed to dry out the exhaust and make more top end power. Buth there is still water spraying into the pipe some to cool the noses.

I would check all the fittings on the pipe.

If it is melting the hose between the pipe and muffler it is typically the fitting and hose feeding the pipe from the water valve.
If it is melting the hose from the muffler to the hull it is typically the water valve.

 

[jchance]

Look at the diagram and make SURE the lines are correct. Also, you say the diaphragm inside the regulator is intact; BUT are the internal parts of the valve loose? If you can grab the top of the diaphragm and the entire internal valve is able to be pulled out then your water regulator is bad. On a good one you cannot pull the internal plastic parts out. I did a write up on this many years ago on PWCToday.com. Your alternatives are to carefully glue the plastic internal back in place or replace the regulator. When it fails it will cause the coupler to melt.

 

[M24per]

Thanks for the insight!

So I did pull the fitting going into the tuned pipe from the WRV and I blew into it and got a bit of resistance. Is this normal for that caled’ fitting?

The water valve closes at higher speed to dry out the exhaust and make more top end power. Buth there is still water spraying into the pipe some to cool the noses.

I would check all the fittings on the pipe.

If it is melting the hose between the pipe and muffler it is typically the fitting and hose feeding the pipe from the water valve.
If it is melting the hose from the muffler to the hull it is typically the water valve.

 

[M24per]

Look at the diagram and make SURE the lines are correct. Also, you say the diaphragm inside the regulator is intact; BUT are the internal parts of the valve loose? If you can grab the top of the diaphragm and the entire internal valve is able to be pulled out then your water regulator is bad. On a good one you cannot pull the internal plastic parts out. I did a write up on this many years ago on PWCToday.com. Your alternatives are to carefully glue the plastic internal back in place or replace the regulator. When it fails it will cause the coupler to melt.

All lines are correct according to the diagram. I replaced the WRV with a “new” one just to cover my bases and the new one doesn’t have that issue where the internals pull out. Just making sure, you mean the plastic “screw on” piece that the diaphragm connects to and that holds the metal washer down to the housing? If so, yeah that stays put. Even after replacing the WRV with said one, I’m still melting the coupler hose…

 

[jchance]

The coupler is cooled by the water flow from the regulator. As rpm’s increase the diaphragm inside the regulator rises and closes the flow straight down into the water box and increases the flow to the tuned pipe. If the flow fails to increase then the hot exhaust will melt the coupler. It is imperative that all of the hoses are hooked up correctly. Just having the 2 small hoses at the regulator reversed will cause your problem. Having the internal plastic piece (part #20 on the earlier drawing) move up with the diaphragm if it comes loose will cause that. Having either of the calibrated fittings whether under the regulator OR where the hose connects to the tuned pipe will cause that and yes they are calibrated. If the hose coming off the pump is flipped to the wash-out fitting it will run but still overheat. If there is anything blocking the flow or decreasing the flow you will get your problem.

As for part #20 inside the regulator, once it is assembled it must stay put. The late Bill O’Neal educated me on how important that valve and proper connections affect a 787. BTW—for those unaware; Bill was one of the early pioneers in PWC racing and was sponsored by Seadoo.

 

[M24per]

The coupler is cooled by the water flow from the regulator. As rpm’s increase the diaphragm inside the regulator rises and closes the flow straight down into the water box and increases the flow to the tuned pipe. If the flow fails to increase then the hot exhaust will melt the coupler. It is imperative that all of the hoses are hooked up correctly. Just having the 2 small hoses at the regulator reversed will cause your problem. Having the internal plastic piece (part #20 on the earlier drawing) move up with the diaphragm if it comes loose will cause that. Having either of the calibrated fittings whether under the regulator OR where the hose connects to the tuned pipe will cause that and yes they are calibrated. If the hose coming off the pump is flipped to the wash-out fitting it will run but still overheat. If there is anything blocking the flow or decreasing the flow you will get your problem.

As for part #20 inside the regulator, once it is assembled it must stay put. The late Bill O’Neal educated me on how important that valve and proper connections affect a 787. BTW—for those unaware; Bill was one of the early pioneers in PWC racing and was sponsored by Seadoo.

I believe you have the idea reversed. If I'm not mistaken it's the other way around, at idle and lower RPM's the diaphragm is down, shooting water up into the tuned pipe, as speed/RPMs increase the jet pump pressurizes the diaphragm causing it to close off water into the tuned pipe and instead shooting water into the muffler/waterbox thru the calibrated fitting.

Either way, as stated before... My new WRV's part #20 is intact and is not coming out, also all the cooling lines are in the correct order referencing the cooling diagram above. My question now is the following: Would the calibrated fitting going to the tuned pipe from the WRV have some resistance to it when I blow into it with the hose connected? I tested the other calibrated fittings above those on the upper part of the tuned pipe and I got no resistance. The reason I ask is because when I look further into it those calibrated fittings DO have a bigger clearance than the one I'm asking about.

 

[mikidymac]

I believe you have the idea reversed. If I'm not mistaken it's the other way around, at idle and lower RPM's the diaphragm is down, shooting water up into the tuned pipe, as speed/RPMs increase the jet pump pressurizes the diaphragm causing it to close off water into the tuned pipe and instead shooting water into the muffler/waterbox thru the calibrated fitting.

Either way, as stated before... My new WRV's part #20 is intact and is not coming out, also all the cooling lines are in the correct order referencing the cooling diagram above. My question now is the following: Would the calibrated fitting going to the tuned pipe from the WRV have some resistance to it when I blow into it with the hose connected? I tested the other calibrated fittings above those on the upper part of the tuned pipe and I got no resistance. The reason I ask is because when I look further into it those calibrated fittings DO have a bigger clearance than the one I'm asking about.

Correct, less water injected at high rpm.

Per the service manual...
At low speeds, water pressure in the supply hose of the regulator valve is not sufficient to overcome the spring of the regulator valve ; more water is being delivered to the injection fitting at the tuned pipe .
At higher speed, water pressure increased in the supply hose of the regulator valve and gradually overcomes the return spring of the regulator valve. Less water is being delivered to the injection fitting of the tuned pipe.

 

[jchance]

Do it however you want but the pressure line coming off the jet pump that goes to the lower rear engine intake that has the T must go to the lower fitting on the water regulator. The upper tubing then goes to the tuned pipe. As pressure rises in the water box the spring is overcome and the flow changes from one to the other output. This is from 29 years of working on 787's. We've owned quite a few of them. Just make certain that neither calibrated fitting is clogged AND the hoses are in the correct position and maybe you may solve your problem.

I also have had 1 single time where the upper tuned pipe was clogged and the exhaust in the pipe wasn't getting enough water through it to cool. The pipe got hot! That problem was due to sand ingestion. The overheat sensor came on that time. Lucky the engine didn't have a problem. Check that while you are at it.

 

[M24per]

Do it however you want but the pressure line coming off the jet pump that goes to the lower rear engine intake that has the T must go to the lower fitting on the water regulator. The upper tubing then goes to the tuned pipe. As pressure rises in the water box the spring is overcome and the flow changes from one to the other output. This is from 29 years of working on 787's. We've owned quite a few of them. Just make certain that neither calibrated fitting is clogged AND the hoses are in the correct position and maybe you may solve your problem.

I also have had 1 single time where the upper tuned pipe was clogged and the exhaust in the pipe wasn't getting enough water through it to cool. The pipe got hot! That problem was due to sand ingestion. The overheat sensor came on that time. Lucky the engine didn't have a problem. Check that while you are at it.

Do you remember if that one single time the upper tuned pipe was also hot? Cause in my case it seems to be just the lower cone and muffler.

 

[jchance]

I seem to remember that both sections of the upper pipe got pretty hot to touch. Much more than expected. I had another upper pipe do just swapped out and took my time getting it cleaned out. What I eventually found was that one of the welded cover plugs was starting to leak when we got it blown out and the area under the corroded cap had a lot of sand. It was the last plug from the engine. I’m still wondering if you have a hose or 2 reversed. If the 2 hoses at the rear of the machine are swapped then it will run but get too hot because your flow to the regulator would be backwards. The engine would still get water but the other areas wouldn’t get enough. Do you have the service manual? If not, go to PWCToday.com and navigate to the Seadoo forum. All of the manuals are in a sticky at the top of the forum. Good luck!

 

[M24per]

Okay makes sense, thankfully my upper pipe and engine are still cool to the touch. No, again, the hoses are all routed correctly I promise haha. My bet is on the calibrated fitting being clogged since that’s the only one I tested that gave me resistance but either way I won’t find out until I get the new on in from eBay.

 

[jchance]

Get the manual though if you do t have it. Those fittings are NOT the same. Make sure you get the correct one.

 

[M24per]

I have both the service manual and the parts manual, I made sure to buy the correct one the one labeled “48” on the side of the fitting. PN #293710048