I have a 92 polaris 350L 4x4 and it just got a new piston rings and it was also bored and honed, but the thing won't idle for crap. I messed with about everything i can mess with on the carb. Everytime you start it whether it's cold or hot you have to pull the choke out, it then starts right up, you go to turn the choke off because it's about die because the mix is to rich and just as soon as you turn the choke off it idles up and then slowly dies. what gives? I'm thinking maybe a crankcase leak somewhere? anyone else have any ideas? Also is there anyway to test for a crankcase leak? any help is much welcomed, thanks

 

Sounds like something inside the carb is plugged...most likely the pilot jet.

 

I thought that too, but then it shouldn't run at all right? Here's the catch it runs fine if you can keep it idled with the throttle and get it in gear, then it seems to run pretty decent.

 

Does your 92 Polaris have an Electronic Throttle Control (ETC)? My 95 Exlporer was idling very rough and turned out the throttle cable was worn (frayed) and wouldn't allow the two post in the control to make contact. I replaced the throttle cable and cured the poroblem. Pull the cover off yours and check, if it's not that I would think it is a carb problem for sure. Possibly some dirt in the carb.

 

3 things to check,.. 1st pull the plug, see if it's lean/fouling, it'll at least point you in the right direction. Pilot jet as previously stated, they can get gummed up, needle,... might try dropping it a notch

 

ya, it sounds to me like something in the carb...your pilot jet is for you idle..you might take that out and spray some carb cleaner in it...the littlest speck of dirt can rob your fuel..but if you've did that already then..I don't imagine it would be your needle or your main jet..because you said it runs pretty dece when giving it gas...I don't know but I think its in the carb...it sounds like your getting robbed in fuel when idling..but also check you cable too...but thats my two cents

 

To check your crankcase for leaks: need a vacume guage, pull pipe off and reeds. I made covers out of pexi glass but read at some point someone using duct tape. Drill a hole and tap it to fit the pump/guage. Bring pressure to 6psi, should be 0 loss for 5min. This is what I've read on here some where. I haven't done this yet. other than the pexiglass. But will perform this when I get the bottom end re-assembled. Hope this helps, good luck.

 

Yep, if the pilot jet is plugged, itll have very lttle gas, coming in at idle. Using the "choke", which is using a starter jet, gives enough to keep it going. Also using more than 1/8 throtle, gets you in the midrange, and it runs there too. I think you did a very good job troubleshooting this, you nailed every symptom of a plugged pilot jet.
When you disasemble the carb, and pull the pilot jet out, you should be able to see light coming thru it, like looking thru a straw, the hole is very small, but you need to be able to see light coming thru...then you know its clean. Sometimes you have to, take one strand, of a 18 gauge braided wire, and push it thru from the threaded side, to the unthreaded side( opposite of the direction that fuel flows), to push out stubborn stuff. The hole is going to be about .012 diameter. If thats doesnt clean it out, get a new jet...theyre about 4 bucks.
let us know how youre doing.

 

One other thing,.. although obvious u may have overlooked the vent line,.. make sure is unobstructed and mounted proper,... plugged vent = no idle

 

I just wanted to say thanks for all the help i'm going home this weekend from college and i will take all these ideas into consideration, once again thanks a lot.