97 Gtx shuts off at 4500rpm

[PhatUnicorns22]

I have a 1997 GTX.
I took this ski in on a trade for a fence repair i did for an older gentleman that had no use for it anymore and asked if i'd take it on trade for a 500$ job.
I have rode skis. Helped be a wrench gofer but never really worked on skis.
He said he rebuilt the carbs last year.
It hasnt had fuel sitting in it.
The ski fires up right away
Put water line on it runs like a champ
Put into the water to test run like a ape til around 35 mph and 4500 rpm then stalls and dies.
So i asked if he tuned carbs he said no.
So i looked that up and have that fixed for now til i can tune it in the water up or down as it says in the manual.
I am going to replace the fuel lines this week and the fuel selector as well.
New filters oil and fuel.
Could there be something else im not thinking of to replace?
Mechanic wants ALOT to work on it.
I dont think its there yet but ill take any advice and things to look for.

 

[Spider4real]

You might have sticking rave valves. I would pull them and clean off all the carbon depots that are likely coating them and make sure they move up and down smoothly. I used to clean mine every year, so it likely time to do yours. Also based on what looks like water stains under the water regulator on the water box, you might have a leak. Common for the bellow to be punctured by the metal clamp that holds it on. I would check that because that can definitely impact higher RPMs if you you have a leak

Edit: but these things should not cause the engine to shut off. You may wish to double check compression.

 

[burtshaver2021]

really just need to set the high and low speed screws to factory settings, it’s always worked for me anyways