Help with stock rxpx260

[Rxpx260dude]

Hi all,

new to this forum and was wondering if you guys could guide me in the right direction in my repair. I am no stranger to mechanics, but I am a fair newbie to watercraft. I have a 2012 rxpx 260 and bought it used in 2017 with 75hrs on it. I do my usual routine maintenance once a year (oil, filter, plugs, antifreeze flush). But this last year I was running into an acceleration issue with the ski. I searched this forum and replaced the wear ring as suggested. It seems that didn't fix the problem 😕. I will now describe what is going on... i would start the ski up, and idle it out of the no wake zone. In drive, if I punched the throttle (once I was clear of the no wake zone) the engine would rev up and vibrate a little bit, but would be seemingly in neutral. I looked at the gauges and it seems that they are reading properly as RPM and boost build up. But it seems almost like I have a bad slipping clutch of some kind (some sort of disconnect between the engine and impeller). After it does that, I slowly get on the throttle and it will get up to cruising speed (60mph) no problem... are there any belts that might be worn out or a driveshaft spline that may be stripped? The wear ring is new and I inspected the impeller and it looked ok, but I didn't pull the driveshaft or check the carbon ring. Any and all help is greatly appreciated

Dave

[K447]

Carbon ring inspection may be appropriate. If the carbon ring is not sealing properly it can allow air to be drawn into the jet pump inlet water flow, aerating the water going through the impeller. This is known as jet pump ventilation.

A properly sealing carbon ring should provide an air-tight seal during acceleration. During initial acceleration from low speed the water forward of the impeller experiences negative pressure. The impeller is literally ‘sucking’ the water in. If there is an air leak then air from inside the hull bubbles past the seal and into the water flow going into the jet pump. The impeller cannot develop proper thrust when the water flow includes air.

Ventilation of the jet pump symptoms includes: high engine revving and sluggish acceleration from idle or low speeds. As the hull gains forward speed (perhaps just as the hull gets properly on plane) suddenly the expected thrust is restored and full acceleration occurs. Slowing the hull to near idle speeds, the problem recurs if hard acceleration is again attempted.

Seadoo has revised the carbon ring materials and related parts configuration several times over the years. Confirm which of the newer versions is compatible with your 2012 model.

Also make sure the groove in the driveshaft for the c-clip is not worn. It is important that the carbon ring and hat assembly not wobble as it rotates.

[Green Hulk]

Hi Dave, welcome to the forum!
Just so you know, there is no forward, neutral or reverse gears on these skis. If the engine is running the impeller is spinning in a forward direction. There is no clutch, transmission, etc.
The neutral and reverse just adjusts the reverse bucket to keep the ski stationary, or moving rearward.

What you are experiencing is cavitation. This can be caused by an air leak at the carbon seal as K447 pointed out.
It can also be caused by a bad pump seal, damaged impeller, or wrong wear ring. If you accidentally installed a 300 wear ring the tolerance between the impeller and wear ring would be too large and would cause cavitation issues.

Hope that helps!

[Rxpx260dude]

Thank you all for your advice, I will replace the carbon ring and let you guys know what I find. Hopefully it isn't a driveshaft because they look expensive. I do have the proper rxpx 260 wear ring in there and it was a very snug fit. Going to order one in a few and hope to work on it next week.

[canuck]

Replace the bellows as well as the carbon seal, you will have the driveshaft removed to do this so it's a good time to check the motor mounts and engine alignment before reassembly.