Cavitation or power issue? - 2002 Sportser 130 hp

[daverooster]

I may have both a cavitation problem and a power issue. Sure feels likes cavitation but also having power issues. This boat allegedly only has about 50 hours on it (bought it recently with 36 hours and a little over 50 now). When first driving the boat (when I first bought it) before it is really warmed up well it sputters and coughs before gaining full power and planning off. Once fully warmed up and planned off it goes great - speedo said slightly past 50 with one or two riders. I replaced the spark plugs and the old ones were chocolate brown. Over the last week (rented a cottage at Lake Geneva, WI for the week - beautiful lake but a lot of weeds) or so the problem has progressed. I've jumped overboard and pulled weeds out of the intake more then a half of dozen times this week. Most recently while trying to pull a waterskier it got much worse and the boat won't even plane off - with or without the skier behind the boat and we limped back to the dock. Of course I jumped overboard and checked the intake and no weeds. The next morning I pulled the new plugs and they were wet - I cleaned and dried them and the boat would plane but the problem was still there. Once planed the boat seemed to run fine. The impellor/pump seemed perfect when I bought it and i have not beached the boat or anything abusive. I've owened many jetskis over the years as well as boats and I know what cavitation is but this has me stumped because it seems like both. I also serviced the Rave values (boy were they gunked up!). I found a post that took me through the entire process and they are now srubbed clean using one of those green scrub pads and easy off oven cleaner with laytex gloves). Seemed to run a bit better but the problem is not gone. When I accelerate and if the sound of the engine is 'ra, ra, ra, ra,' which should be a smooth continuous sound the sound is very much 'ra....ra....ra....ra....ra' meaning higher pitch, lower pitch repeat, prior to planing off and the rpms are high like +7K. Not sure why it would not plane off at all yesterday. One thing is for sure when you nail the throttle it is not instantaneous GO!, more like no go. Tomorrow is our last day here and then I can pull the boat out and check things out more thoroughly. I was hoping that it might be something minor that I was overlooking so I could get one last day of boating in before my vacation ends. What else....practically starts the second you hit the start button, idles fine...

 

[Dr Honda]

1) The RA-RA-RA sound is the engine bouncing off the rev-limiter.

2) Cleaning plugs in a 2-stroke is useless. Put in new ones.



With that said... you have bad cavitation. And with the level that you are describing... it's an air leak. AND... the most likely place is from the carbon seal.

So... remove the gray cover behind the engine, and make sure the stainless ring didn't slide toward the engine. Then... push the stainless ring toward the transom, and see if you have a second clip position. If you do... move the clip to hold the seal tighter. If you don't... replace the carbon ring, boot, and the O-rings in the stainless ring.

 

[daverooster]

View attachment 14494

 

[daverooster]

Update: I pushed the stainless 'Seal Carrier Ring' forward and I was able to see the 'C-clip' but there was no 'O-Ring' which I assume retains the 'Seal Carrier Ring' (goes between the C-clip and the Seal Carrier Ring). I now know my full problem and the fix - big Thanks to Dr. Honda! Any advise on the repair would be appreciated. Thanks again
How hard is it to remove the drive shaft?

 

[Dr Honda]

the O-rings are inside of the stainless ring. So... you will only see them, if you remove the ring from the shaft.

When you pushed the stainles ring forward... did you see a second clip spot. (about 3/16" from the first) If you did... just put the clip there, and call it a day.

The carbon ring is a floating design. SO... if you push on it... it will move around.

Removing the shaft is easy. Pop the clip off the driveshaft that holds the stainless ring. Then, remove the pump, and it will slide out the back.

 

[daverooster]

Update: I pulled the driveshaft and it only has one groove. Should I just assume that the carbon ring is worn and replace it? Maybe I will need to add a spacer too? Is the stainless 'Seal Carrier Ring' supposed to be able to slide over the C-clip to the point where you can't even see the C-clip? If not I suppose I should be replacing this too? Also, contrary to my earlier post while the prop looks pretty good the wear ring seems to be shot like it disintergrated or something. The gap between the wear ring in the prop is probably an eighth of an inch, well maybe not that big but its really big. Doc Honda thanks again for the help!

 

[Dr Honda]

The stainless ring will cover the C-clip... but you can always see it at the end. Basically, the stainless ring captures the C-clip, but it doesn't slide in.


You shouldn't need a spacer. Get a new OEM carbon ring, the 2 O-rings for the stainless ring, and a new boot. It should solve your issues.

 

[daverooster]

After more then a week away from this repair (work related travel) I'm back at it. My first mistake was that I should have bought the tool to remove the impeller. I was lucky that my local motorcycle/jet ski shop had one and pulled the impeller off for me. I also did not order the synthetic oil for the pump bearings but got lucky when a Sea Doo dealer had this and the 'O' ring. Now here is my current problem if I am to use the boat this weekend: without the tool to remove/install the impeller I can't attach a torque wrench to tighten the impeller to 70 NM or 52 ft ibs. Anyhow, I wrigged a way to tighten the impeller on my vise and hand tightened the impeller with a standard open end wrench. I basically tightened it about as hard as I could with one hand/arm with my other arm wrapped around the unit. My concern is actually that I may have over-torqued it versus under torqueing. Here's why: now when I rotate the impeller it turns easy but then resistance builds a bit and then it spins easily again for a few inches and this 'build up of resistance then lack of resistance occurs' over and over again. In my experience that is the sign of bearing being too tight. Any advise on this situation - with the goal of using the boat tomorrow versus ordering the impeller removal tool and losing another week of boating this late in the season - ? Thanks as always for your help!

 

[daverooster]

Ok, here's what I did in regard to manually torqueing the impeller: I put a bolt/nut in my vise and put my torque wrench on it. I torqued it to 52 lbs/70 NMs holding the torque wrench about 10 inches from the head (same length as my open end wrench). After doing this a couple of times I quickly torqued the impeller to approximately the same torque from memory. Not scientific but the best approach I could come up with. Tomorrow I'm going to install it and try it in the water - I hope this works!
One more update: Sunday 12:30 PM: All back together. Only one last glitch. I filled the cone on the pump with synthetic oil - kept waiting for a bubble and then added more until I was certain that it was filled all the way. I put the little threade plug back in with an allen wrench and the plug would not seat it seems to just keep going in. In fact I was worried that it would fall all the way through so I just stopped. Im very concerned that this thing is going to leak oil and the only thing I can think of is to replace the entire piece to be sure. Does anyone have experience with this issue? Please help! Happy Labor Day by the way!
A second update: so I put the boat in and ran it for a couple of hours today. It ran fine - way better than before for sure. It planes off pretty fast but it seems to cavitate briefly for a second while planing. Does anyone know if this is normal or if it should grab and go flawlessly? All in all it seems to be running very well. I visually inspected the cone after pulling the boat out to see if there was any visual evidence of oil leaking and there was none. I also looked at the wear ring from both sides of the impeller and I was surprised to see that the black wear ring material was already peeling back some? Does anyone know if this is normal after just installing a new wear ring? I'm hoping it is and that something else isn't wrong. Here's the thing after I installed the new wear ring I noticed some defects on the interior of the ring - not sure how these things are made but looks like a worn 'tool' or defective material. I'm trying to download some images for feedback.