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Discussion Starter #1
Hi THere, new guy, I have a 1990 Polaris 500 LC, It starts fine, idles for a few seconds, and then the clutchside cylinder does not continue to run. If I rev it up, it fires off, but then shortly stops running, eventually the engine dies, but will restart when I choke it. I have cleaned the carbs and checked the fuel pump. A friend said it might be the crankcase seals, especially the clutch side one. I'm asking how I check this out. I have pulled it over and the tube that runs the fuel pump doesn't seem to pulse any pressure which I assume runs the fuel pump. Put new plugs in, and the right side piston fires and runs fine even when I rev it way up, the clutch side just doesn't seem to be getting any fuel.

Any help would be great.

Thanks,

Bill
 

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Welcome Bigg, let's eliminate a few more things before you tear the engine down to get to the seals. Explain clean the carbs! If you have not taken the pilot jet ( along with the main jet and the fuel inlet needle and seat) out of the carb, and cleaned it so you can see thru it, the carbs are not cleaned. Do you have compression in the left cylinder? On the cylinder that does not run, when you take the spark plug out, is it wet or dry? Way back when I had a 89 Indy 500, after about 5-6 years, the brass connection inside the spark plug cap broke, and caused that cylinder to quit running, make sure you check the caps out. Usually seals don't go out unless the sled has sit, unused, for a long period of time, or if you have had a belt fail, and thrash the seal when it came off. Indy 500's, as a rule, don't usually eat belts.
 

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Quick check for the PTO crank seal. Start the sled and keep it running . Spray starting ether on the shaft seal, if the RPM's increase the seal is leaking.
 

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Discussion Starter #5
Thank you, I'll try all those things, when I checked the carb it all seemed clean, but I'll recheck, also checking the wire. I'll report back.

Thanks again,

Bill
 

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i'm having the same problem,i have a 1987 polaris indy trail 488. i will start the snowmobile and it will run fine, but if i try to go it will bogg out at 4000 rpm's, then i will have to feather the gas to get it back up the high rpms for it to bogg out again. then to restart it i have to use the choke or i cant get it started. i check the plugs and it looks like the clutch side cylinder is not firing or to much gas ( when it does run it looks like its running rich, alot of smoke).
i cleand the carbs out good, i put new plugs in it. but i dont know were to start with tuning or sync the carbs. i rebuild race car engine all the time for the local race track so i am familer with engine. this is my first snowmobile so i want to ask questions before i do anything. if some one could point my in the right direction with tuning the carbs i would be greatful
 

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There are 2 screws on bottom of the crankcase under your exhaust y pipe, undo the screws and see if there is fuel in the bottom. if there is your needle and seats could be the problem causing fuel to leak, or more then likely your fuel pump diaphragm is leaking. :withstupid:
 

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Ohh forgot to mention pilot airscrew on carb sould be 1 1/2 turns out. Also check choke plungers to make sure their not sticking and adjust for 1/4 inch play at control end. :withstupid:
 
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