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  1. #1

    07 rxp only 7500/7600 rpm *updated* 18APR20 it's fixed, solution posted

    Hey guys. Having a problem with my rxp and hoping you guys can help narrow it down. For some back ground I bought it towards the end of last season with 165 hours on it. He claims it had a fresh rebuild, supercharger included with the updated washers. It ran great the couple of times I had it out(but still only 7500rpms). Season ended so it got winterized and I changed oil and plugs and all. I took it out for the 1st time this season today and again, it's running great but only 7500rpms and 60.x mph(gps verified). If the ski jumps out of the water itll jump to 81xx, but other than that it never does.(it will also hit 81xx on the trailer) Everything is stock. It has a solas 14/19r. It's a little beat up, so that's getting replaced now. I cant figure out why the rpms are low, I was hoping the impeller was wrong but nope. Any ideas? If theres anything else I can tell you about it please ask. Thanks guys.

    More info:
    Oil: new and correct level(right between the marks)
    Plugs: brand new .030 gapped
    Impeller: solas 14/19r. A little beat up, getting replaced with a new one now

    There was a small plastic thing stuck behind the impeller we found after riding today. It's something we picked up and not from the ski itself. Not sure if its relevant though

    update: just pulled the hoses off of the supercharger. both have a bit of oil in them and i can spin the s/c by hand...its very tight, and difficult, but if i push hard enough, the s/c wheel will move some. does this mean its time to rebuild? i suppose this could be the cause of my low RPM if thats the case.

    what else should I check while this thing is down/apart? I would rather get it all done in one shot if i can. thanks guys.

    here are a couple of pictures of the supercharger. is it obvious if these are ceramic or stainless washers? I'm new to these so I'm not too sure just by looking. Are there any obvious visual issues here? I'm heading out to grab a tq wrench now and will report back with slip readings.

    slip readings: i spun the nut a little over 1 full rotation before checking and its sitting right at 65in/lbs.
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    Last edited by Adam4pt6; 04-18-2020 at 04:00 PM. Reason: update

  2. #2
    Next update. The intercooler holds pressure and shows no sign of leaking.

    Any ideas?

  3. #3
    JT jpt7779's Avatar
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    You are on the right track. I would send the SC to Jerry for rebuild service: http://greenhulk.net/forums/showthread.php?t=146938

    65 in-lbs is only 5.4 ft-lbs that is definitely on the low side of slip.

    from the shop manual (www.brpmanuals.com)

    new SC 80-124 ft-lbs

    break in SC 71-106 ft-lbs.

    A good rule of thumb is capable boost of SC equals foot pounds required. (ie 10 psi boost = 10 ft-lbs).

    You have NO real idea how old the SC internals are without documented proof, so I would suggest getting this critical part done correctly by an expert!

  4. #4
    I appreciate the reply. the shop manual i found showed what I have to be in spec (44-88 lbf/in as per the "2007 seadoo shop manual) but maybe my info is out of date?

    as it sits now I've pressure tested the intake(whole engine to be more accurate) and it holds pressure fine. what i did find was a problem with the little hose that comes off of the throttle body and goes up to the yellow cap on the engine cover (i believe this is to fog the throttle body?). once i put any pressure into the intake(pre throttle body) it would come un capped and leak air out. with this pinched off the engine would hold pressure with no issues.

    so, where im at now is

    S/C has 65 in/lbs of resistance
    intercooler holds pressure
    engine(intake to exhaust) hold pressure
    any pressure applied causes that yellow cap to come off and air to bleed out.


    so is it really as simple as capping that piece off and my problems should be gone? its clearly a boost leak....(hell, in theory i could replace this with a boost gauge i suppose right?)

    and based on those pictures can anyone tell what kind of washers those are? I dont mind swapping them out for the new correct ones if needed, but would rather do it if i need to or should, not because i "might as well while its apart." to be fair ill probably replace them either way, if theyre ceramic ill do it now, if they arent then ill do it at the end of the season.

  5. #5
    Bob 1tommygunner1927's Avatar
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    Its not the newer style washers you need to be concerned about, its the bearings that may or may not have been changed, and the shaft too. Anyone could change the washers and say the S/Cer was serviced! If you don't know the seller and/or no paperwork for a S/Cer rebuild, Suggest sending it to Jerry, ASAP!

    Weather has a huge effect on performance, and a messed up wear ring or impeller also degrades performance.

    Soapy water can help locate boost leaks, and helps clean up a dirty engine compartment. Get to work!


  6. #6
    thanks for the reply. that does seem like the right answer. no arguments on the supercharger comments at all.

    as for weather, definitely understood there. our last outing was 65 degree air temp and 50-52 degree water temp. we are right at sea level (+10ft to be technical). to me(and i am by no means an expert, so please correct me if im wrong) that weather shouldn't be pulling 5-600 rpms away from me.

    wear ring and impeller are also a topic for me right now(made a second thread as i figured they were two separate issues). it has a 14/19r in it, bearings and all feel good. its a little beat up, but its not having cavitation issues. its on the replacement list, and im trying to figure out what is best for a stock ski.

    as far as boost leaks. i pressurized the intercooler and found no leaks. i also pressurized from the supercharger inlet to the exhaust outlet and found 1. the small hose that goes from the throttle body to the yellow capped piece that sits on the engine cover. With pressure applied that cap easily popped off and leaked off pressure. with that temporarily pinched shut the motor hold pressure fine. right now im leaning towards that being my boost leak issue(seems obvious at this point). I plan on closing that off and running this thing again to see what happens.

    i would like to figure out how to install a boost gauge so i can monitor boost levels and see if there is a potential leak that i missed. I also need to figure out what size impeller to run, if the 14/19 is a little too big and is taking some RPMs away from me that would explain a bit too.

  7. #7
    Bob 1tommygunner1927's Avatar
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    Check vitals of the engine: a compression test and a leak down test.

    Remove injectors, send out for cleaning/flow test.

    Check ECU for any trouble codes....dealership or professional pwc repair shop, or buy CanDoo.

    Search this section for impellers for your model to see what others have done for impeller pitch.

    Weather is more than air temp/elevation....barometric pressure and humidity also play a role......Relative Air Density!

    Because its a 2007 ski, I'd check every electrical connection for corrosion, clean'em, and dielectric grease all, and check the overall condition of every component.

    Last item....engine alignment! Check it, correct it, and replace carbon seal/hat/bellows.

  8. #8
    compression test is on the to do list. I'm going to try to pick the tool up from a buddy tomorrow.

    injectors are a good thought that i didn't think of. My only thought(not that I'm discounting that idea at all) is that typically with injector issues I've seen things fail to run great in general. usually an idle issue or a little breaking up or something. This coming from an automotive background. Again, not negating that thought, it just wasn't at the top of my list because of how smooth it runs up to and at 7600rpms.

    ecu is another good one, I'll find a shop or dealer near by and see if i can get it checked out.

    I've been searching a ton on impellers and I'm finding both 13/18 and 14/19 recommended. I'm not sure which to go with... I dont want to be on the limiter, but dont want to be leaving 500ish rpms on the table either. I'm still reading what I can on the topic and trying to make the most educated decision I can.

    Agreed on weather, I have a drag racing background as well as a long range shooting background where ALL of those factors matter(i found that rolling them all into a DA reading was pretty efficient for cars/long range guns. I've got a kestrel, I'll dig it out for my next troubleshooting outing), so agreed. I didn't note barometric pressure or humidity yesterday as it was a "typical" day and I can't imagine an unfelt change in those causing this much of an issue.

    engine alignment is not one I thought about. I'll do some reading and learning about that. I'm curious about the issues it can cause now that its been brought up.


    At the end of the day this one is my wifes ski. I'm not looking to make it any faster than it should be stock, just looking to get it running at its full factory potential.

  9. #9
    Bob 1tommygunner1927's Avatar
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    Injectors can seem fine.....until they're cleaned/flowed and suddenly rpm is back up! I'd also pull the fuel pump assembly and change the fuel sock.

    Your lady will appreciate you going to such lengths to avoid problems out on the water. If not, you'll hear about it! LOL

  10. #10
    Rebuild that SC unit. Two different types of washers and 65 inch lbs is way toooo low and it probably worse when running and warm. Looks like someone slapped the blower together with what ever they could find.


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