1996 XP - Water Valve Regulator/ Water Box and bogging?

[shattered00]

Hello All,

Yet another summer is here and I am still fighting the second 96 XP. A quick recap of my ski's symptoms. Ski has instant throttle response out of the water and revs up fine. Placed in water, ski either dies when throttle given to fast or throttle won't have any impact on forward movement. Even when slowly depressing the throttle, ski will sometimes get up to maybe 10mph but bog and/or die. Ski idles fine in water for as long as throttle is not depressed. Ski has no positive impact when choke is pulled halfway or all the way while trying to depress throttle.

For actual video of the issue, please check my original thread. 3 years and so close with one 1996 XP - still bogging

Here is what I have done so far. See below that for my question regarding the waterbox/ water valve regulator

- Changed the fuel selector valve/switch ( I tried to find new OEM, but was unable to - I ordered one that said OEM but was not - stamping was from Taiwan in unmarked box).
- Replaced the water separator and ensured it had a new o-ring
- Replaced all grey fuel lines with USCG rated black fuel lines - verified no obstruction in any fuel lines with air compressor
- I have changed the inlet and outlet valves for the fuel tank (one of which goes to the outside of the ski to relieve pressure)
- Changed the rectifier (also tested with red wire disconnected and did not fix the issue)
- New fuel is in the gas tank with slight amount of oil per the manual on new engine break-ins
- All clamps corresponding to fuel lines/carbs/water separator have been tightened
- Carbs have been cleaned out (compression shot through the nozzles to clear out any debris with carb cleaner being shot through after to make sure they were open)) and rebuilt with a genuine Mikuni kit along with Mikuni 80gram black spring and Mikuni 1.5 Needles(viton tip)/seats
- Carbs have been set to factor specs (Low 1, High 0) - I have also tried low from 1 to 1.5 with no difference noticed)
- Carbs have now been rebuilt by a jet ski shop (one of the butterfly valves was found to be bent from what the mechanic said was likely a rare backfire so I had to cannibalize one of the carbs from the second 96 and give to him and he combined them - the second set also had one carb which had a bent butterfly valve again which he said was really rare). Pop off pressure is good, etc. per the mechanic. I really thought the carbs were going to be the problem but it did not change the symptoms at all.
- Cleaned Rave valves
- Changed spark plugs and gapped properly - NGK Br8es
- Rotary valve timing confirmed proper
-Compression 150 in both pistons (engine newly rebuilt)

There is a small oil tank leak somewhere, so I am not sure how that could cause this problem, but just mentioning it in the event that someone can confirm that could cause the bogging issue.

I have been searching the interweb and came across this thread: 1996 won't rev over 1/4 throttle in water. Completely rebuilt. What now? @TurnerBFC @Matt Braley

In the thread, Turner appears to have a similar problem as me. Braley suggested a broken baffle in the water box and subsequently mentioned a bad water valve regulator. Per Braley, to diagnose the waterbox, I would pull it and shake it while listening for a rattle so I will do that, but also later in the thread it is mentioned that Turner replaced the hose and that fixed the issue and that the water regulator valve was also damaged and replaced. Which hose was replaced? The large one that goes from the waterbox to the back of the ski for the exhaust port? What did replacing the hose do to fix it?

How do I tell if the water regulator valve is broken? Is the water regulator valve the "rave" thing that looks like the two rave valves on the engine? Does this seem like something that could be my problem? Braley mentioned that if the hose was soft then the water regulator has failed. I haven't been able to see a leak but I haven't really been able to ride without seat off. Which hose would I be looking for and does soft mean something like that the material is degrading?

Apologies for the long post and all the questions, but I am crossing my fingers that this is the problem. Thank you all for any help.

 

[mikidymac]

Are you 100% sure the mechanic used genuine Mikuni parts and did it correctly.

 

[shattered00]

Yes, I supplied him with the Mikuni parts. He had to use two different size springs to get the pop off pressure to be the same on each carb. He operates Krenn Power Sports and actually used to race 96 XPs back in the day and was the only mechanic in the DFW that would actually work on 2 strokes. Cost me a pretty penny but I needed to rule out the carbs being the issue.

 

[noviceskier]

Yes, I supplied him with the Mikuni parts. He had to use two different size springs to get the pop off pressure to be the same on each carb.

seems like the carbs may still be your issue then, that's a no no. Take them back

 

[shattered00]

Ah, he used 80g in one and 95g in the other from what I understand to get the pop off pressure in both carbs at 32psi. He said when 80g was used in both carbs one was outside of the tolerant range. How would I get the pop off pressure to be the same if I use two 80g springs? Have to trim the spring a little bit?

Edit: at least im fairly sure he said that. It is possible that he said he used the 95g in both instead of the 80grams that I gave him. I will verify on Monday.

 

[mikidymac]

You have to use two 80 gram springs, you can’t stagger them or cut them. If they won’t pop close to the same it’s the arm or the needles and seats causing the difference. Someone didn’t do it correctly.

 

[shattered00]

Ugh, that cost me $350 too which I felt was a steep price but I was desperate at the time since I have failed on my own to get this thing running properly. Thank y'all for the information. I was realllllly hoping that the waterbox thing could be my issue. Even with the 80g springs I had in before I took it to the mechanic, the ski still exhibited the symptoms, so I am not sure what is wrong with these carbs. A fuel pressure test was done and everything came back within spec.

 

[Matt Braley]

I was talking about the big rubber hose that goes between the waterbox and the outlet. Some of them are weak and squishy when you squeeze it from the outside. They separate from the inside when skis run long periods of time without enough water flowing through it. A good hose will feel like a good radiator hose without pressure in it.

Sucks about the carb job. The are available new for 400ish. I know it's not book correct but I have used different things many times to get an equal pop off and been fine. I don't think your carbs are causing your problem.

 

[Matt Braley]

Did you try bypassing that cheap fuel valve? It could be sucking air in. Try running a line from the RES or the ON barb on the fuel baffle to the inlet of the carbs. You can put a cheap 1/4' inline filter in there to make sure you don't suck up debris from the tank during the test. Also I can't see the impulse line in those videos. It's not clogged or kinked is it?

 

[shattered00]

Thank you for the reply. The hose appears fine based on what you described. I will bypass the fuel valve after getting an in line filter and test that out as soon as I can get back to the lake and report back.

Also, no kinks or obstructions in impulse line. Took off and blew out with air compressor. I also just ordered new carbs for $400 and will put those on if nothing else works. I need another pair of carbs anyway for the third ski down the road when I get to putting it back together. Thanks!

 

[shattered00]

Just thought I would share this pic of the bellow for the rave water valve regulator....

Also ordered the Purolator F20011 for the in-line fuel filter.

 

[mikidymac]

Very common on the regulator. If there are no holes in the black rubber diaphragm just replace the rusted clamp.

I would caution you not to use the inline filter once you figure out your issue. For temporary diagnosing it will be fine.

 

[shattered00]

Thank you for the info. Just above my thumb in line with the screw clamp is a hole. I will order a new one.

 

[mikidymac]

You can use a zip tie if you melt the end so there are no sharp edges. I use two wraps of stainless safety wire on them.

 

[shattered00]

I have everything back together. I am now in the process of trying to adjust the red caps on the two rave valves and the water regulator. Currently, the rave valve caps are inward where they line up with the 3rd "tooth" on the black plastic piece that surrounds the cap. The water regulator cap is outward where the top of the cap is flush with the top of the black surrounding piece.

Is there a tool that I can get which will allow these caps to be adjusted? I have been trying with two flathead screwdrivers in the slots on the cap and have had little success in moving the caps...

 

[mikidymac]

Adjust them before putting the caps on. The water regulator adjustment should not be messed with as it is set from the factory and really doesn't have a how to set procedure that I have ever seen.

The engine ones can be adjusted wherever you want as long as they are the same and just moves the rpm up or down as to when the open.

 

[shattered00]

The latest test run was somewhat of a success. I have two questions below.

I re-routed the carb intake fuel line directly from the gas tank to the carb and that did not change anything in terms of the bogging/hesitation and dying when throttle given. I had ordered the new carbs, but didn't realize that I ordered the ones with the accelerator pump (didn't even know they made those). I did not have small houses with me and was not close to any hardware store so I disconnected the pump for the time being and put them on. I then ran into a frustrating problem.

First question: The return line fitting as indicated in the photo below (not the exact carbs) is MUCH larger in diameter than the return line on the original design 787 1/4 inch fitting. For the life of me, I could not get 1/4 line over the return fuel fitting. I tore up my knuckles trying to force the line over the nozzle. I ended up drilling out a small portion of the line to widen it as a temporary solution so that I could at least get on the water to test the ski. What are my more permanent and safer solutions for this problem? When I got back home, I tried searching for a fuel line that goes from 1/4 to a larger diameter size on the other end since the baffle nozzle on the gas tank is 1/4 and the return line on the carb is much larger. Or am I missing something altogether that goes on the return nozzle before the fuel line?



Second question: Referencing the photograph below for how I put the water valve regulator back together which appears identical to how it was when I took it apart, it is leaking where the top black cap overlaps with the bottom half of the black "base." The leak is not the threads where I screwed the metal piece into the exhaust (used loctire 592) nor is it where the black "base" screws into the metal screw that then screws into the exhaust (used plumbers tape). The leak is a steady drip, so I am not sure if I have to line something up or what I did wrong in putting it back together. I used the metal clip for the time being as I didn't have big enough zip ties just fyi.


Leaking from portion circled by yellow.

All in all, the ski ran with slight bog at 1/4 throttle and needed to be feathered slowly to get over that hump but then ran better. This was with the new carbs.

Thank you for the help!

 

[mikidymac]

The jetting on the carbs is different with the accelerator pump so you can't just disconnect it or you will be running lean.
I have never seen carbs with a 5/16 return, but they do have a 5/16 supply on the newer ones, are you sure you don't have the hoses backwards?

If the water regulator is leaking it could be from the body being warped which is pretty common. Up until now the only solution is a new housing. On mine and another member here we decided to try an o-ring from Home Depot in the groove shown below and after one season it appears to be working fine but this is an at your own risk mod.

 

[shattered00]

Thank you for the response! I appear to have been using the wrong terminology. The hoses are hooked up right but what I have been calling the return line appears to actually be the supply line. I have taken a picture of my actual setup and you can see the bulbous part of the hose that is barely on there after drilling out the inside. I believe that this must be a 5/16 as you suggest but my question now is how big of a deal will it be using a 5/16 hose for the supply line since the nipple on the fuel baffle that goes into the gas tank is 1/4? If I clamp it real tight that should prevent any air leak I presume? I guess the new carbs use 5/16 so more fuel can get into them? Thanks again for all this info!



I will also get an o-ring and try that out if I can't find a new housing. Thanks!