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  1. #1

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    When adding RR SC impeller and 42's

    Any information on adding these two items to a RR Stage III and seeing a slight difference in idle. Prior to adding these items my ski would seek RPM at idle anywhere between 1500 and 1700 rpm (I don't even know if this is normal for high strung ski.) Now boat seeks RPM between 1350 and 1750 at idel. Is it the new injectors running rich or just a tuning issue? Before adding when the boat warmed up it would only deviate RPM by 100 or so at idle.


  2. #2
    Vern's Avatar
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    I just added an A kit SC and 42 lb injectors. I noticed the idle was a tiny bit rougher, but my rpms go from 1700 - 1850, slightly more variation than before. I noticed the exhaust now has some gas in it ... I can see a faint gas trail in the water when it is idling on the lift - definitely a bit richer at idle for me. I have a 2005 RXP with Riva Stage 2 + the above stuff now.

  3. #3
    Moderator Franko's Avatar
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    My RR stage 3 ski with a B kit idles at 1700-1850. It fluctuates more than it did before. Yours fluctuates quite a bit though.

  4. #4
    Been there and back! BDNJ's Avatar
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    Guys: With my B kit and 50 lb injectors, Nil's/Brian's controller/mapping made it wayyyyy too rich. I had to idle around @ 2300 to keep it from stalling. Plus, it would not start easily. I had to lean it out from 500 rpm to 2000 rpm on the controller. I know that GP and his tuners had troubles with the 42 's and the RR wheel. I think their testing skis ran better with the stock injectors. - However, I'm not sure if these skis were Stg III or not though.

    More than likely the 42's are dumping full fuel at idle causing the bog in idle.

    Just my .02.

    Brendan
    Last edited by BDNJ; 07-28-2006 at 04:29 PM.

  5. #5
    mxl16's Avatar
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    Quote Originally Posted by BDNJ
    I know that GP and his tuners had troubles with the 42 's and the RR wheel. I think their testing skis ran better with the stock injectors. - However, I'm not sure if these skis were Stg III or not though.
    i was told the test ski was as follows: new rr imp, rr ic, and riva air intake. the 42s ran rich, stock injectors worked the best.

  6. #6
    suck my wake's Avatar
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    Stock my idle was pretty solid at 1800 and now since I put my 42's and RR wheel in my idle does fluctuate from 1760 to 1800 but I have not noticed a signifigant loss in cruise range or any overly rich conditions. Even on an 85+ degree day the ski ran great and also ran the fastest numbers. The only thing I have noticed is a little hesitation from a dead stop when racing someone but other than that everything performs well.

  7. #7
    im with suck my wake. I notice a little hez on bottom. not so much to be noticed but with years of tunning. I also idle all day at 1800-1850 with my 42's.

    BDNJ- I took your advice and ordered the controller but havent seen it yet. I also am going with the better head mod. I reamed my guides out a lill to much. cant wait to see everyone at buggs.

  8. #8

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    Try taking the sensor out of the waterbox and attaching it to the water line. You don't need 42's unless you have head work. It will be a little lean around 7,000 but wide open is good to go. This may change if you ride in below 60 degree air.

  9. #9
    suck my wake's Avatar
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    Personally I am going to stick with the 42's, I am already knockin on 81mph @8400 rpm's in 85 degree temps and it will be cooling off around here soon so it will only get better. If I get an A/F guage maybe I will play with it but until then I would rather be a little rich, its much safer that way

  10. #10

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    Exclamation For immediate release.

    Guys I found the answer and it is 100% right. From Rotax Racing in Austria- A polished and ported Stage III setup with these add ons RRSC Impellor, 42's. There is an ajustment to be done- Adjust cam shaft timing to achieve 130lbs compression minimum. Mine at 134lb now with idle flux of 150 rpm. SKI RUNNING REALLY STRONG.

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