2013 RXT No throttle, full throttle..bog, no bog Random RPMS

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I'm kind of stumped on this one.

Its a 2013 RXT. Trying to help out some friends. They just bought a ski, put 2 hours on it. In the mean time they apparently got stuck on a sand bar but instead of getting off and lifting the ski off the sand/silt bar they just plowed through it with the engine.

When I looked at it, it had the exhaust overheat code going on. Looked at the exhaust temp sensor and the metal part was still in the big exhaust/muffler part...but it had separated from the plastic piece. It was literally laying in the hull still connected to the wiring harness.

I installed a new sensor, I even removed every hose from jet pump inside the hull going to the exhaust and back out. Even the ones going to the intercooler. I disconnected them and looked through them all...no dirt,no debris...all is clear. I even took the pump off to check to see if there was anything in there to clear out, nothing.

I did find that the reducer plug was messed up. It is the green oring with like a metal washer in it...well,there was no metal center in it at all and the oring was all kinds of squished...so I installed a new reducer. I checked out the wear ring, it certainly wasn't new, but nothing that would cause issues.

I took the ski out for a test drive, cleared all the codes and rode it. Immediately something isn't fixed. The ski rides awful. The throttle means nothing at all. It is SO random. I can have the throttle all the way in and it revs just above idle. I can release it and try again and it will idle then spurt up to 7k rpm then 4k, then 8k, then idle, etc etc. Sometimes it will literally jump out of the water and plane off immediately and haul ass for a split second then the RPM's go all over the place again while the throttle is being held steady. Sometimes I can run it WOT for 10 seconds and then it suddenly drops to 5k, then 10k, then WOT, then idle, then 2k etc etc.

The revs are certainly matching the speed of the ski...as in...its certainly not cavitation. If it was a wear ring, it would rev rev rev just no go go go right? Or at least take forever to go go go right?

It doesn't sound like its bogging (like a 2 stroke that needs a carb job ya know). It's almost like the throttle is just dead sometimes.

I get back to the dock and read codes...nothing. Not a thing. It certainly isn't overheating anymore. I'm assuming it did at one point overheat badly since it melted the plastic sensor out of the exhaust temp sensor. I'm guessing they flushed out all the silt/sand that they sucked up.

Anyways, any ideas of where to start looking for next?

I did a compression test, all 3 cylinders are good and were exactly the same. I used diag software to check coil and check injectors firing. Tomorrow I will pull the injectors off and have them flow tested, as well as checking for water in the fuel. Also I figured I would check the supercharger for slippage.

Question: If a supercharger is slipping badly, or getting there...what is the symptom? Isn't it just that I will have reduced top end rpm and speed? It's not necessarily going to run like crap any time and all times at random?

FWIW, the ski is actually VERY clean with absolutely minimum if no corrosion. No other signs of electrical issues or what not. What else should I be looking at? Plugs looked good too, like maybe 20 hours on them? nice and white still and starting to get that tan color to them, dry.
I would definitely change the plugs, 4tecs eat them for breakfast


Update. I checked out several things today. I wanted to check the fuel to see if there was water in it. Disconnected the fuel rail...inserted key to prime the pump and fill a big mason jar. Fuel was good, absolutely no water or debris.

I then hooked up the fuel rail to my homemade flow tester. And essentially the first run, the #1 injector was running about 40% more fuel than the other two. I mixed it up a little with different connectors/positions and run it several more times and they all flowed even. So, not sure if I just happened to clean that injector, or something in my rigging was giving favor to that one injector. I'm not sure. It was certainly dumping a lot more fuel though, and the others were neck and neck at 66 64cc and #1 was at 100.

Anyways, I checked out some other things to rule out. I disconnected the intake to the throttle body. Powered the ecm on, and used a mirror and light (in my mouth) to check the throttle plate was opening and was opening relative to the throttle lever as I was using it. I Also checked the diagnostic software to make sure the TPS was reacting accordingly too. All was good.

Ohmed injectors...all good, about 12.6 on all 3.

And then I put it all back together and put new plugs in. Also grabbed some extra coils from a 2004gtx (same part number). Ended up not needing the coils though, was planning to swap all of them to see if made a difference and then individually swap them to find the bad one.

All is well. So maybe it was only the spark plugs, maybe it was just that fuel injector hung up...or both? I've pulled many spark plugs, and these ones looked really good. Odd.
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