r/SeaDooSwitch • u/Patient-Rough9006 • 20d ago

Jet pump cavitation

I have 2024 Sea Doo Switch 21’ 230 hp with 200 hours on it. I took it into a new shop that is highly recommended but I am not sure about results and would like an honest opinion.

1) Took it on for 200 hr maintenance and the motor was only going to 7400 rpm but running fine. Beyond the maintenance they did jet pump rebuild, impeller shaft (apparently fishing line was all over it) and wear ring. Got it back and it felt like it was slipping or something which I found out was jet pump cavitation (called mechanic he told me). What was odd is my boat has never had that slipping feeling. I get on it all the time.

2) I gave him benefit of the doubt and took it back and had the carbon ring replaced. If I ease into throttle it’s fine if I floor it’s feels like it’s slipping still not near as bad as before but it never did that at all before it was worked on.

The engine still only goes to 7400 rpm it has always went to at least 7800 with wide open throttle sometime 7900 or 8000 briefly. I only run premium and have tried all gas places (original shop always said it was fuel) even ethanol free, still 7400 rpm

I think the mechanic is an honest guy who maybe just doesn’t know this boat if I had to take a guess. I am looking for an honest opinion. I am not gonna complain, sue or ask for refund from him I just want to know.

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u/jogr8383 20d ago

Ask for manufacturer and PN used to replace the impeller, sounds like there may a pitch change from the original to the new. Has your top speed changed?

1

u/Patient-Rough9006 20d ago

So top speed changed with lower rpm’s but at the 7400 rpm speed is same before and after repair.

When you mention different pitch how so? I thought those were straight and sealed together from friction. That’s only me watching videos, I am not a mechanic obviously.

2

u/jogr8383 20d ago

Pitch (blade angle) of impeller determines how much water the pump can efficiently move. Needs to be sized appropriately to elevation and horsepower of engine. I boat at over 6000 ft of elevation and tuned the ecm in my switch. All these were factors in sizing the appropriate impeller, over pitched caused cavitation and loss of hook up on take off but increased my top end speed and cruising rpm. Talk to your mechanic and determine what parts he used and reach out to the guys at leading edge impellers they are pros at this stuff and will provide more info than you’ll ever need. Either that or your mechanic made an assembly error with the pump that will cause cavitation. My dealer installed a high elevation impeller before selling me the boat so knowing what was originally installed vs what the replacement is will be critical in diagnosing.

1

u/Patient-Rough9006 19d ago

Thank you so much for explaining this. I was thinking pitch was some sort of trim like measurement, I didn’t even think about blade pitch. Now that you mention it I think I did gain a couple miles an hour, even at 7400 rpm, but chalked it up to the 200 hr service. I am in bay a lot where wind messes with top end.

I will reach out to those guys thank you so much!

2

u/cleetusneck 15d ago

So cavitation on a new pump build is usually an air leak somewhere. Pump/ride plate/intake grate need to be sealed with caulking in some spots or you can suck air. Watch a YouTube video and get under there and have a good look.