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  1. #11
    Myself's Avatar
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    Have a look at the reeds on that cylinder.

  2. #12
    Quote Originally Posted by Myself View Post
    Have a look at the reeds on that cylinder.
    Good suggestion. Just pulled the PTO reed and it looks fine. No light visible and all 8 valves pop when you press on them.

    This is a recently rebuilt motor and it started acting up after its first WOT burst after 5 hours of careful break-in. Compression was fine immediately afterwards but maybe I need to check again. I also just checked the PTO rave value and it moves freely. When the motor blew last time, the rave caught a piston ring and got jammed.

  3. #13
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    not shaving the rave valve after installing oversize pistons on a di is a classic mistake

    if I'm not mistaken doesn't the DI only run on one cyl at idle, or was that the RFI?

    other things to consider:

    air compressor output
    fact that the air injectors are quite old now, and are subject to failures that do not throw a code and can turn out to be an intermittent problem under full load ( when their duration is longest)

    the di's are at the end of their cost effective service life sorry to say. They were great skis till about ten years ago.

  4. #14
    Quote Originally Posted by nmpeter View Post
    not shaving the rave valve after installing oversize pistons on a di is a classic mistake

    if I'm not mistaken doesn't the DI only run on one cyl at idle, or was that the RFI?

    other things to consider:

    air compressor output
    fact that the air injectors are quite old now, and are subject to failures that do not throw a code and can turn out to be an intermittent problem under full load ( when their duration is longest)

    the di's are at the end of their cost effective service life sorry to say. They were great skis till about ten years ago.
    Although there are mixed messages on various forums, I am pretty confident the DI idles on both cylinders. The service manual mentions nothing of a single cylinder idle, unlike the RFI.

    I broke down today and hacked my high pressure air line to test the air compressor. It tested good with >110psi dead head. I put air to the fuel rail and it regulated at a constant 78 psi, so that looks good as well. When I held 78 psi to the fuel rail, my fuel pump would only give me 60. Odd because I have seen higher in the recent past but all signs are now pointing to a fuel pressure issue.

    Plan for tomorrow is to rig up something to test the pump individually as it could be the fuel pressure regulator. I think I am getting close on this one!

  5. #15
    To close this out, my pump is the problem. Put a needle valve on the pump outlet and it would not get over 60 psi. At least I know what the problem is!

  6. #16
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    Quote Originally Posted by WaarrEagle View Post
    To close this out, my pump is the problem. Put a needle valve on the pump outlet and it would not get over 60 psi. At least I know what the problem is!

    sorry to say your problems are just beginning, since running DI pumps are a pretty tough find these days. Do lots of research on the topic before plunking down for any pump that claims to "work in a DI"

  7. #17
    Quote Originally Posted by nmpeter View Post
    sorry to say your problems are just beginning, since running DI pumps are a pretty tough find these days. Do lots of research on the topic before plunking down for any pump that claims to "work in a DI"

    Ha, I have seen the discussions for years but never paid that much attention since my OEM unit was working. Looks like the Quantum units are fairly well regarded for the DI's, the HFP-342DI in particular but now a new model is out that looks more like the OEM design... the HFP-500DI. Anyone have any feedback on the new unit?

  8. #18
    Myself's Avatar
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    I used one last year with the long brass neck that looks like the oem unit.......still going like a champ!


  9. #19

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    Quote Originally Posted by Myself View Post
    I used one last year with the long brass neck that looks like the oem unit.......still going like a champ!
    Quote Originally Posted by WaarrEagle View Post
    Ha, I have seen the discussions for years but never paid that much attention since my OEM unit was working. Looks like the Quantum units are fairly well regarded for the DI's, the HFP-342DI in particular but now a new model is out that looks more like the OEM design... the HFP-500DI. Anyone have any feedback on the new unit?
    I ordered one for my 01 GTX di and the HFP500DI came. The plug was different so I contacted highflow. They said they sent me the wrong pump and I should have gotten the 342. I asked about the fact that the 500 looks like the factory one, but they said it wouldn't fit. I find that kind of hard to believe. It looks identical and now I see it looks like "myself" installed one. How did you do it? Did you just have to swap connectors? Highflow also said that it runs at ~48psi. So the regulator must regulate it down to 27 psi and the compressor adds 80 psi for the 107 psi right?

  10. #20
    Quote Originally Posted by Blackhawk36 View Post
    I soaked it and I attached a hose to it and partially filled the hose with carb cleaner. Then modifying what MYSELF suggested I pressurized the line to 60 psi and tapped the injector connectors with 12 volts. The carb cleaner sprayed out so I figured I was good. Put it all back together and no change. I think I am done. I see a new or slightly used SeaDoo in my near future.
    Did you every figure out the problem? I'm chasing the same issue right now!

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