Troubleshooting the Rotax Racing Stage I kit (was problems)

[Jarrett]

*****UPDATE: All of the initial problems I was having have been resolved and have been documented in this thread. I am leaving this thread up so others can use it for help getting their ski running well. Mark has been great to work with and the kit is performing as advertised or better now. Latest results are 75-76 MPH. I would definitely buy this kit again if I were modding another RXP. Check the last couple of pages for full details*****


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Ok, it looks like there are a few of us having problems getting high RPMs with this kit. I thought we could start a thread to hopefully work through our issues together. Here's my results today:

Air: 88
Humidity: 58%
Water temp: ~80
Gas level: 7 bars
Wind: None

Previous mods:

Riva Power Filter
Riva grate
No OPAS
Worx sponsons
Impros repitched stock @ 12/19.5
Normal RPMs: ~8050 (in cooler air)

New Mod parts:

RR ECU
RR IC w/ plumbing kit
RR heavy duty clutch (minus inner washer, had to use stock)
Vortech SC impeller

1st Run:
RR ECU in
1st pass: raced up to 8100 RPM then hit a glass celing and eased down
2nd pass: eased up to 8050 RPM then stuck there
Oil warning goes off and I limp back to shore and add oil until its right in the middle of the indented space on dip stick

2nd Run:
RR ECU in
1st pass: 7650 RPM max - no attempts to go above
2nd pass: 7700 RPM max - no attempts to go above

3rd Run:
Stock ECU - no knock sensor piggyback
1st pass: 7200 RPM
2nd pass: 7400 RPM peak, but mostly 7300 RPM

4th Run:
Stock ECU - knock sensor piggy back installed
1st run: raced up to 8050 and hit glass ceiling then fell back and raced up again.
2nd run: pretty much the same with RPMs all over the place. I saw things like this while holding WOT

7650, 7700, 7900, 8050, 7700, 7800, 7800, 7900, 8000, 7650, 7700, etc.

It was like the ski was fighting to get up to 8100+ Sometimes it would be running at 7700 and then lurch forward to 8050 and then drop back down. Really weird. This was only with the stock ECU. With the RR ECU it would hold at 7650 or so and not try to jump up.

I also tried running with the seat off and it seemed to make no difference. With the exception no knock sensor/stock ecu run, the ski was pulling harder than normal. Spinning the prop big time on bottom and ripping through the mid range once it caught. Then it would quickly hit that weird sputtering RPM thing on top.

Mark's recommendations:

Check SC slippage. Said its possible to do it on the ski. Take off the Riva air filter, gently put a broom handle inbetween the PUMP impeller so it won't turn, then put the torque wrench on the SC impeller and turn counter clockwise and watch for the range where the SC slips. Should be 10-12

His other recommendation is to pull the outerwear on the Riva Power Filter. He said it might be too restrictive for the ECU and is choking it down.

Jerry, do you have your outerwear on or off?

Anyone else having issues like this? Any ideas? Thanks.

[CRAZEDRXP]

I can guarantee it has nothing to do with that outwear sock Both jerry and i did a few days worth of testing pulls with sock on and off that sock is not as restrictive as people think ... it blocks moisture not air ... .. Im just curious how many hours on your ski? is it the original wear ring and s/c clutch ?

[CRAZEDRXP]

O i have one more thing .. your problems seem to start after ur warning light went off and u limped back to add oil ... any chance u added too much oil??

[CRAZEDRXP]

I know u said and made it clear u added oil until it was rite in the middle .. but was the motor definitley 100% warmed up and full operationg temp ... IF not oil in the middle at cold or even somewhat cold is way to high

[Green Hulk]

Mark's recommendations:

Check SC slippage. Said its possible to do it on the ski. Take off the Riva air filter, gently put a broom handle inbetween the PUMP impeller so it won't turn, then put the torque wrench on the SC impeller and turn counter clockwise and watch for the range where the SC slips. Should be 10-12

I think you and Frank need to do this! Something has to be going on in that clutch.


I think you may have put a lil too much oil in. Put the oil mark just above the bottom bend and see what happens.

Other than that i'm out of suggestions
I'm really hoping you find the issue with the clutch!
Can you put a stock ceramic in place of the RR heavy duty one? I thought the RR one was thicker???

[rx4pain]

Oil level - my guess.

[Jarrett]

Thanks for the feedback. Here are some answers:

Not stock wear ring, but it's definitely not in good shape. But my understanding is that goofed wear rings give high RPMs and low speed, not low intermittent RPMs.

The clutch was stock before we installed the RR HD clutch at ~72 hours. After the RR ceramic washer broke and fell into my engine, I put the stock one back on. I am running two shims. We did a slip test at one point and it slipped at 15 pounds. I need to do another one to be sure.

The ski was definitely warm when I added the oil. If putting the oil right in the middle of the bend is too high, then that could be an issue. But I have seen it at that level before when the ski was running right.

I don't really believe the outerwear is the issue. If the air intake was too restrictive for the RR ECU, I could understand that. But it doesn't explain the weird RPM with the stock ECU that has been giving good numbers up until now.

I'll try the slippage test and drain a little oil and see how it goes. Is there anything else that could be the culprit here? As I understand, I should be seeing 8350+ RPM at this point and I am far from that.

[rx4pain]

Damn - I hate hearing bad news about things I'm about to buy. I was going to just stick with the BOV with the intercooler and keep the SC clutch stock with the SC impeller. Now I've been talked into doing the RR massive super duper clutch kit and this is what broke and fell into Jarrett's engine?

[two2curupt]

You did retrieve the ceramic parts from the internals of your motor did you not??

[Jarrett]

Pain, it was a faulty install on my part that started the whole mess. It seems if you do the RR HD clutch install right the first time, it works.

Two, no the ceramic washer is still in there. Dealer is going to pull it for me next week.