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  1. #1

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    250x a full tank of full, 3 passengers (450lb), 61mph

    Took the ski out with fresh plugs and rebuilt pump. I polished and debured the impeller.
    Opened it up and it topped out at 61 with 3 people and a full tank. Yes I checked the speedo with gps. Mine believe it or not it is dead on or a little slow.
    Does that sound about right?
    Boost was pegged, rpm was near 8k. Forgot to set the dash to digital rpm.


  2. #2
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    How are you making 8000 rpm on a 250 ?

  3. #3
    Moderator #985 lasportsmn's Avatar
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    Sounds like you may have demurred the impeller too much. That would cause the high Rpms causing the high boost yet no speed. Cavitatimg or lost pump efficiency are the causes of those symptom.

  4. #4

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    I couldn't see the tach very well, too bright out. Forgot to set it for digital rpm. The debur was from a couple of light rock nicks. Then polished it up. No slip or cavitation I could feel or see when it was rebuilt.
    It was towards 8K not at it.
    Will the tach record the max rpm reached?

  5. #5
    nicjak's Avatar
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    no the tach wont record the correct max rpm, you need to watch the readout in digital mode.

  6. #6
    the wotman likes boobs wotman's Avatar
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    Quote Originally Posted by Dezl_Dr View Post
    Took the ski out with fresh plugs and rebuilt pump. I polished and debured the impeller.
    Opened it up and it topped out at 61 with 3 people and a full tank. Yes I checked the speedo with gps. Mine believe it or not it is dead on or a little slow.
    Does that sound about right?
    Boost was pegged, rpm was near 8k. Forgot to set the dash to digital rpm.
    i think 61mph with 3 x people and a full tank sounds about right.

  7. #7
    Take the time to smile sirbreaksalot's Avatar
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    Quote Originally Posted by Dezl_Dr View Post
    I couldn't see the tach very well, too bright out. Forgot to set it for digital rpm. The debur was from a couple of light rock nicks. Then polished it up. No slip or cavitation I could feel or see when it was rebuilt.
    It was towards 8K not at it.
    Will the tach record the max rpm reached?
    Smiles all round I feel

    Waz

  8. #8

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    Update, full tank, my son and I today riding. 7600 rpm and 63-64.

  9. #9
    Dr. Evil's Avatar
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    How big were the three people? 61mph with 3 full size adults and a full tank sounds pretty decent to me and also probably over the max load limit, which is under 500lbs and I think that includes fuel, cargo and passengers. Gas weighs 6lbs per gallon and the tank holds 20.6, so a full tank is a little over 120lbs. My '07 250x puts out similar numbers to what you're quoting riding with your son, - 63-64 (to about 65-67), though I've never taken three people. I won't even take one other person unless I have to. I'm very selfish.

    My top speed with only me and full tank and all my junk seems to vary between around 63 and 67. But it's a little hard to tell because the speedo is constantly all over the place. It's not steady like my STX-12F was. It's always moving around. Sometimes, especially in chop, but I've also noticed it in smooth water, I'll be cruising at a steady speed, like say 50 for example, and I'll notice that the speedo will suddenly drop way down to the 20's and 30's and eventually recover. My 12F never did that either.

    You may not be aware, but the digital display has a memory that will retain your top speed and rpm until you either exceed it or manually reset it to zero -- it's explained in the owners manual. From what I can tell, it retains a new reading whenever either the new speed is higher or the RPM is higher. It appears that either number will trigger a new reading in the memory, whichever one first exceeds the previous high reading. I know the highest reading mine ever retained in memory was 70mph and I'm not sure what rpm that was at but I wanna say it was around 7850. The 70mph may have been a momentary fluke, because that isn't a number I see on a regular basis. But then again, maybe mine is hyperpowered from all that gas in the oil.

    The factory service manual says the speedo sensor should be 4.5mm from the bottom of the sensor to the bottom of the hull. I measured mine as best I could, it ain't easy to get a precise measurement, and it appears to be right on the money.

    I just went out in the garage and checked the current reading in the display memory, since it's after midnite and I have nothing better to do than drink beer and read these threads. Anyway, my current reading is 68 mph and 7620 rpm. I do not know whether the rpm reading and the mph reading happen together, but I assume they do. We'd have to ask Kawi to know for sure. But I can tell you that I usually have the display set for trip miles rather than rpm, so I monitor rpm with the analog gauge and I routinely get 7850 or 7900 out of it. I'll have to remember to try the digital display so I can get an exact number, but I did compare the two gauges once and they were very consistent with each other. So I'm pretty sure if I see 7800 on the analog gauge, that's what I'll likely see on the digital as well. The display is so much better on the new 300's. The display on ours is really a weak point. Those gauges are just too hard to read. MPH is Ok, but fuel level and everything else is a pain in the ass. Hope you're not a proctologist, Dr.

  10. #10

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    My son and I go about 280 pounds together. We had a good time, he is only 7. He was driving, racing his mom on her stx12. I let him open it up for a while, my nerve left me and took over just before we ran up on some 2' rolling waves. The tach and speed would be way off now, we stood up and had to hold it under power to cross the waves, the jet drive unloaded and caught several times. Sounds cool, like the race videos I've watched.
    The rpm stays around 7580-7600, the speed stays nearly the same now matter what load is on the ski. I like it, handles well pulls a tube easy, just uses a lot of gas.

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