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Thread: What Next!

  1. #1
    Joined
    Jul 2004
    From
    Meeker, Oklahoma
    Posts
    19

    Default What Next! SL650 Std

    Just purchased 2 1995 Polaris SL650Std. One runs perfectly the other is a problem. Problem is getting on top of the water. If I slowly increase the throttle I will get on top of the water and run good not great and as long as I do not come to a complete stop. It idles good and I can let off the throttle and open it wide open with small hesitation, just can't come to complete stop. Once stopped, it is slow getting up, but never dies will always idle good. To get up I have to slowly increase the throttle. Here is what I have tried. Ran Polaris carbon cleaner through the fuel. Changed all 3 plugs BRP7ES while cold. Started and ran great no problem for about thirty minutes then hard to get on top of the water. Changed the plugs when warm and still hard to get on top of the water. Changed the fuel pump still no difference. Made sure fuel hoses and filters were clear. Compressions reads the same as the one that runs great. Lookling at the plugs they appear to be running lean, so I took it out and adjusted the high speed in 1/8 increments with no success, also adjusted the low speed 1/8th at a time with no improvement. The only time it runs great is if I let it set over night and put in 3 new plugs and this only last 20 to 30 minutes. What do I try next?
    Last edited by rswann; 07-13-2004 at 01:51 PM. Reason: Title Change

  2. #2
    Joined
    Jul 2004
    From
    marysville
    Posts
    8

    Default Re: What Next!

    i have a polaris 900 sl and i had a similar problem until i rebuilt the carbs, and
    don't be afraid to burn it rich it wont hurt the motor one bit , it will just make
    it last twice as long as everybody elses who run lean,extra oil is a good thing,
    the carbs are very basic to rebuild , get a service manual if you don't already
    have, there very handy.........hope this helps you.

  3. #3
    Joined
    Apr 2004
    From
    Tampa, FL
    Posts
    155

    Smile Re: What Next!

    I agree with Lance and you should look at the carbs especially the needles and seats etc. A rebuild of the carbs would be a good idea on a ski of this age. You also may want to check the reeds and see if they are not closing all the way.

  4. #4
    Joined
    Jun 2002
    From
    Charlotte NC
    Posts
    1,868

    Default Re: What Next!

    It sounds to me it may be a pump problem since he can give it full throttle and it won't die and the rpm's come up. Ifyou have to slowley come to speed it is the pump cavitating bad.

    Not sure why it would work fine for a while after sitting overnite unless the gas tank vent is cloged and it won't allow fuel to the carbs because of a vacume in the tank. Next time it happends try unscrewing the cap and see if you here it pull air in.

  5. #5
    Joined
    Jul 2004
    From
    Meeker, Oklahoma
    Posts
    19

    Default Re: What Next!

    I pulled the carbs and cleaned them took it to the lake and ran Great the first trip to the lake. Pulled the plugs and the front 2 plugs looked good. The rear (PTO) plug was Very lean and the GAP on that plug was almost closed. Reset the gap and turned the high speed out 1/4 turn. Next trip it ran good but not near as good as the previous trip it would not not reach top speed. Turned the high screw back in 1/4 and still no help. The only thing left is to close the gap on the plug, how would this help? But, the only time it has ran great was when the plug had very small gap. What does this tell me? Could someone explain how the Spark plug gap affects the way it runs? I also have an identical SL650 that runs perfectly. So I swapped the fuel ppumps and neither machin ran differently. How can I get full power back?

  6. #6
    Joined
    Feb 2004
    Posts
    46

    Default Re: What Next!

    It sounds like to me that there is a very slight timing problem. This is how I see it...it runs good at first, since the elec. stator and flywheel are cold or slightly warm, then after 20mins. the problem starts, the stator/flywheel are now really warm, even hot. Remember things expand when heated and this may be enough to throw the timing off just a bit if it was on the edge when it's cool. This also explains why it works better with the smaller gap on the plug...it's compensating for the slight timing being off. I would check the stator and flywheel to make sure it is aligned properly...but don't ask me how to do it on this watercraft...good luck!
    Top End - A great place to be!
    00' SLX
    00' SLH
    98' SLTX

  7. #7
    Joined
    Apr 2004
    From
    Tampa, FL
    Posts
    155

    Thumbs up Re: What Next!

    Have you tested the sparkplug leads and ends for continuity? Have you cleaned the ground wire connected to the motor plate? The spark plug boots should have 5k ohms resistance and if you check from the boot to the ground in the electrical box should be about 3k more so around 8k ohms resistance. Sounds like it may be electrical since it heats up and then doesn't run good. I would open the electrical box and go through it making sure everything is tightly connected. Do some basic continutiy and ground lead checks to see if everything is ok. You may want to start with taking the sparkplug boots off and cutting back the leads about 1/4 to 1/2 inch and screwing them back on to make new contact.

  8. #8
    Joined
    Jul 2004
    From
    Meeker, Oklahoma
    Posts
    19

    Default Re: What Next!

    Thanks for the suggestions, I will the above recommendations. If nyone else has ideas let me know.

  9. #9
    Joined
    Jul 2004
    From
    Meeker, Oklahoma
    Posts
    19

    Default Re: What Next!

    Pro racer, checked the plug wires from the boot to the watercraft ground, did not open electrical box yet. Here is what I found the back two plugs read just over 8K ohms and the front plug read as an open but the plug was still firing. After cutting this plug wire back 1/4" and put the boot back on it read approx 8K ohms just like the other 2. Here is my question, can the plug still fire it the plug wire is close to the boot but not touching? I will go test it tonight and see if there is improvement.

  10. #10
    Joined
    Apr 2004
    From
    Tampa, FL
    Posts
    155

    Thumbs up Re: What Next!

    I have seen where I took the plug boot off and it read open however the ski ran. I replaced them anyhow and it runs much smoother. It could arch across a small gap but obviously not the best scenario.

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