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  1. #1

    polaris 780 no acceleration

    ok 97 polaris 780 wont accel in the water. so far i have overhauld carbs, replaced all fuel lines, replaced fuel tank check valves.removed thermostat becouse it was stuck closed, has good compression. like i said its only on the water it runs bad on the trailer it runs fine will idle fine fires right up the first time no feather the choke or throttle. but in the water hard start feather choke. get it off the trailer and do a circle in the water wide open throttle and no go let off and it dies. and hard to start while i float further away from the ramp. i thought maybe limp mode because no mfd so i pulled it off my other ski and its all reading fine.


  2. #2
    urugol's Avatar
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    Did you adjust your high/low speed screws to factory specs? Does it bog down on take off? This is where I would be looking for starters.

  3. #3
    i left them right where they were since it ran fine last time out and it wont go over like 5mph so yeah on take off

  4. #4
    urugol's Avatar
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    You may have a fuel delivery problem to 1 or more cyls. I would start by testing each individual cyl, fire them individually 1 at a time with the other 2 disconnected - you can fire the engine on 1 cyl at a time to check that you are getting fuel and spark - you already have compression so that's a good start. Before you do that I would also check the intake grate and pump make sure there is nothing blocking the passages.

  5. #5
    just look up underneath or what

  6. #6
    urugol's Avatar
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    Get yourself a torch, go under the ski and check the tunnel where the intake grate is you should be able to see the drive shaft and no blockages, aka seaweed, dead fish etc. If all is good flash the torch inside the jet pump ensure the impeller is clear no sticks or other foreign matter in there.

  7. #7
    ok i did that all good dident know if there was more to it

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    urugol's Avatar
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  9. #9
    also i will run on cyl one and two but not three has spark there

  10. #10
    urugol's Avatar
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    So you can start up on either 1 or 2 but not on 3 on it's own?

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