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  1. #1
    SUV1200's Avatar
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    SUV 1200 - Max RPM 7K / Max speed 37?

    My buddy picked up a 2000 SUV1200. Compression is 95 across the board, has new plugs, starts right up. Only does 37 max right now and only reached 7K RPM before starting to bog/cough.. Would this be carb related? Supposedly has a new jet pump. Runs on premix.


  2. #2
    Yamaha artisan Cutlass's Avatar
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    That compression is way low. Time for a top end

  3. #3
    SUV1200's Avatar
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    What is typical redline for the 1200? What components make up Top end? I sold my 2002 with 100 psi compression and it still banged 48 mph.

  4. #4
    I dont think your compression is way low. Mine is registering 95~100 on an AutoZone gauge and I can stil hit 60+ mph all day. I pulled my head and everything looks just fine. I do wish compression would be higher but not about to break into an engine that runs so good. One thing I can tell with the autozone gauge is it's threads are not very deep at all - meaning with the gauge installed there's more volume inside the combustion chamber than with spark plugs. 10~15% difference could mean an extra 10~15psi. Also you might get lower numbers if your powervalve is involved in the test. Is this a powervalve engine??


    If you are concerned about engine compression (And - because you ARE going too slow)...Pull the head and find out more of the story.

    Also, the dial mph in the rear is inacurate, but it should read higher than 40mph.

    RPM vs speed isnt exactly linear; I mean, at 4000rpm you might go 20, at 5000rpm you may only go 35~40. At 7000rpm you should go 60+. I think 7100 rpm is stock max rpm. Being that it's a boat rather than a ski you might see lower numbers

    You might have carb problems.

  5. #5
    I have a 2001 SUV and top speed is about 45 maybe 48 on a good day. Compression is 120 across the board. I do agree with CUTLASS that the compression is low and with it being that low top performance is going to be down slightly.

    Put a fresh set of plugs in it and run it for about 30 minutes (on the water). Run it wide open throttle before you bring it back in then kill the motor (do not idle in and turn it off as this will give you false readings on the plugs). Pull the plugs take some pics and post them on here so we can see what they look like. This will tell you alot about how the engine is performing.

    Black = Rich
    White = Lean
    Brownish = Good

  6. #6
    SUV1200's Avatar
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    Thanks guys! Will also check the clearance of the prop to ring this week

  7. #7
    Put a 12/19 Solas prop on mine this weekend and a new wear ring and it was night and day difference on the performance of the ski. Before it would cavitate so bad that I had to ease into the throttle to get it out of the hole. I may have lost a little top end speed but that does not bother me as these are just cruisers anyways. Also put a R&D Cavitation cone on it. It made my SUV a sweet ride!!.

    Just a note in case you have Prop problems.

  8. #8
    Sorry man I may give you a little more INFO than you need but hate to see a SUV brother having issue. Here are the specs on your LOW/HIGH speed adjustments for a stock ski if you find the plugs to look unfavorable

    HIGH SPEED SETTING SHOULD BE 3/4 TURN ON 1&3 CYLINDER AND 1 ON CENTER CYLINDER. I HAVE MINE AT 1 TURN WHICH WORKS BEST FOR WHERE I AM LOCATED.
    LOW SPEED SHOULD BE 1 ON ALL.

    If you find the need to adjust always do it at 1/4 turn increments

  9. #9
    Yamaha artisan Cutlass's Avatar
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    Yeah, I suppose gauge quality could be a factor in the low compression numbers.
    A typical 65U will run about 6800 rpm at top speed. could be a little more or a little less.
    The SUV1200 doesn't have powervalves.

  10. #10
    I have 3 different SUV's. two of them are 2001 models and one is a 2001.one has a brand new motor which I have yet to test compression on and the other one has 95 across all 3. I have a little trouble getting out of the hole on that one however, it pulls off 52 mph all day which is a half of a mile an hour less then my friends 2004 SUV that has a brand new fresh rebuild.his SUV has close to 120 across all 3 FWIW.

    Oside Bill sold me his Solas prop before he passed away so I want to install that on this ski to see how much of a difference it makes before I jump into conclusions on that hole shot issue.

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