Hi, Usually I'm pretty good a diagnosing and repairing just about anything but this has me stumped,actually posted something about this last winter.To the point,my 99 runs perfect,plenty of power,no smoke and I stay on top of maint.Last winter I did a typical oil/filter change using the Polaris kit which may have nothing to do with the symptoms.After the oil change I started it and let it idle and double checked the oil level which was fine,several hours later I started it up to pull it in the shop,started fine and my wife was trying to tell me something so I shut it off,It restarted fine but had to turn it off again for a phone call this time when I tried to start it,it was like starter hit a brick wall,so I tried it again and it started fine so I decided to try it several more times and it did it about 3 out of 10 times,remember the engine was still cold.I figured it was the new colored oil Polaris come out with so I changed it again using Mobile 1 and a Wix filter and it still did it but only cold,once it warms up it will start fine no matter how many times I try.I replaced the starter,starter drive,battery,checked all connections,replaced the decompression lever spring,checked the cam,while in it there the rocker arm had a light groove from the decompression ball so I replaced it as well,checked everything electrical I could think of.All summer long it never did it again until this morning,temps got down in the low 50's.Any ideas on this one?Perhaps it has always done this,usually I let it warm up without shutting it off.The first start when cold even at 20 degrees is fine but if it is switched off before the engine warms it will do it. Crazy

 

I too have a 99 sportsman 500 If I start it cold and let run for just a few min. then shut off an TRY to restart SOMETIMES it will to sound as if it is LOCKED UP ! let sit afew min. hit the starter a couple times and away it goes . I aslo have a 2006 that will do the SAME THING ! talked to my dealer about it I even showed them on my 06 one day they say it gets a compression lock, to let sit a min. hit the start slightly or pull the pull rope a lil [if you can] to relese the lock !!

 

Odd? I guess it's common then seeing your does the same thing,most people when they start it up they continue to leave it running and ride.I found out by accident.It runs perfect so I guess I'll ride on.Thanks for the reply

 

Your dealer is an idiot.

 

Other than his dealer being an idiot,do you or anybody else have any suggestions on the issue or had similar related problems?

 

my 97 -will do it , but it has an11to one wiseco piston in it , I think it is caused by compression, mine always starts and runs fine bit it will stop the starter somtimes, I dont worry about it.

 

My theory is to do with oil viscosity and the decompression system.I noticed last year when looking at the decompression lever while the engine was cold it would not rest against the stop to hold the ball up to release the compression regardless of the position of the cam.I pulled the lever and checked the shaft for burrs as well as unusual wear but found none,I decided to replace the decompression spring which has very little preload,although the manuals states the dcomp lever should rest against the stop,it does not always,it will with the engine cold only if the spring is preloaded one turn which is a no no because the enging would stay in decompression mode or if it is wiped free of oil.I found when cold the thickness of the oil would not allow the lever to operate freely enough to return to push up the ball to allow contact with the exhaust rocker to allow decompression,when the engine is warm and the oil thinner the decompression lever will return each time.As mentioned it starts perfect even in 20 degree weather on the first start,my only conclusion to this is the engine was warm when it was shut down during the last use allowing the lever to operate free and return to its rest.I'm going to ride it till it quits and not worry with it but after alot of experimenting that is my only conclusion, cam to lever tolerance/oil viscosity.

 

you guys might be flooding into the combustion chamber causing hydralock,,,,,,,,,change needle/seat.thats why if you keep running its ok,shut off, fills cylinder with fuel,liquid don't compress,,,,,,,,,,,,next time it happens remove spark plug,maybe no longer locked -up.

 

Actually changed the needle/seat.I thought hydralock at first as well.I can go out and hit the start switch and it will fire up quick without the choke all winter and will run fine all day but if it is switched off before the engine is fully warm and try to start it in say 3 seconds after switching it off it will act as if it is locked up,hit the starter again and it fires up.I did try pulling the plug when it does it and the cylinder is dry but why winter and not summer is what puzzles me,plus I always shut the fuel off when I'm not riding.I rode it 8 hours today on trail rides and it run perfect.I've worked on ATV's for years and this one has puzzled me good even a buddy of mine a the Polaris Dealership is clueless,if you read my initial post I found out this by accident last winter.I suppose I like a challange and there is no need for me to switch it off after I start it when it's cold so I guess I'll ride it till it quits then I can solve it.

 

Check the belt and EBS on the front clutch.