2017 GTI SE 155 only hitting 45 mph and 6250 RPM

[Duluthmatt]

I have a new to me Seadoo with 29 hours that starts and runs great, pulls skiers and tubers fine, but will not go above 45 mph or 6250 RPM. I am missing nearly 1000 RPM and 8+ mph per my reading. If I have it on the lift and briefly rev it will go above 7000 RPM without a load. Does not matter if in eco, touring, or sport mode. I am using a yellow key that comes across as "normal key". New spark plugs installed, no change. Ran with seat off as I read somewhere an exhaust leak can cause poor performance that will improve with seat off - no change with this. I have ran about a tank of gas through it, several sessions of pulling kids on tubes and no changes. There is no shaking, smoking, mis firing. Idles fine.

Brought to dealer and there was some wear on wear ring and they said a small rock was in the pump and removed it and replaced wear ring. Impeller and pump looked OK. Runs identically after the new wear ring and rock removal. No cavitation. I was skeptical about the pump being the issue in the first place and still am, feels like the engine just does not really want to go on the top end.

This Seadoo was in a rental fleet, I talked to the shop that serviced it and nothing has been done other than winterization.

Any suggestions for the next thing to have dealer check? I don't have any specialized tools and want to be an informed customer. Is it possible the key is limiting me even though it says normal? Any suggestions are great. Thanks

 

[Guardpilot]

I have the same exact issue for the second season in a row. I own a 2011 GTI 155 SE. Max speed I can get is 40-44 and RPM 6450. My dealer said run two fresh loads of gas they. Still not hitting 55 like I used to. I did a major overhaul 2 years ago. Just broke 172 hrs, always dealer serviced for winter. All maintenance items completed. Any ideas?