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Discussion Starter · #1 ·
Hey I have a 1991 Polaris indy SP and ther is something wrong . I will go out for a little drive not fast and it will foul the pull cord side plug and act like it is running on one cylinder till i get to about 4900 rpm then it would work wicket anything below that it just wont run good . What i done so far. I took both carbs off put new throdle lines on go some people to set up and clean my carbs propley so they were both sync And it still does the same thing. Im thinking that it is one of my chokes sticking on a little but i dont know. Im going to put a primer on it anyone else got any ideas what clould be going on. Im starting to loose faith in POLARIS
 

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Is the plug in that cylinder that won't run wet or dry when you pull it out of the motor??? This info will help us to help you better.
 

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Thats a horrable reason to lose faith in polaris. Your machine is a 1991, and unless it's had a pro taking carew of it sience it was new, it's enevitable that something will happen. Probabley a quick fix. What kind of compression does the bad cylinder have? Plug condition? Backfires?
 

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Are the plugs wet, if so did you adjust the carbs right, and what size is the sled.
 

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Discussion Starter · #5 ·
Yea the plug was wet and the carbs are done right i got some buddies who know waht their doing set them up. No it dosn't backfire or anything the plugs i put in it had good blue fire then i would go for a drive and the fire iun that one plug wold not be good red and missing. Its a 500. I got 119psi and 119psi both dead even. thats pretty good right.
 

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either the choke, the pilot jet, a broken needle (!), or your needles and seats....

One of those, guarenteeed.

-Dean
 

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dont give up bud i had a 92 500 yu couldnt kill that thing...its gotta be sumthing simple...bad ground...poor connection...bad plug wire...water in gas....maybe the cdi box....
 

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Hey Wheelman, don't loose faith in an old 500 polaris, they are great sleds. It also may be a bad plug cap or coil wire. Start cheap and work from there, I had a bad plug cap snap me in the a$$ once, $4-5 fix, just a thought. Good luck.
 

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Discussion Starter · #11 ·
No its not a bad plug wire or connection and the plugs i put into it were gaped and both had real good spark
 

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Excuse me for sounding stupid, is it case reed? I dont remember.
 

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Try the anti-foul plugs, don't ask the guy if he has them, they don't like to sell the they very rarely foul, tell him you want anti-foul plugs, the plug number is different it is still a 9 plug but the letters are different, they work very well, that's what I use in my sled.
 

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If spark is good and compression is good then its in the carb. If your wet fouling, its dumping fuel in there from either the choke hanging open or having an object (dirt or crap)stuck under the choke plunger, or the needle and seat are junk or plugged with something, or the float is set way to high, or a combination. Its not the main jet, not the pilot jet, not the jet needle. Take the carb off and totally disassemble the sucker. Everything. Clean every passage and inspect all the components. Put her back together and set the air screw, idle and syncronize the carbs. Like Willson said, I have had carbs apart several times and not seen the one little problem until the 100th time.
 

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Well the guys seem to have a great handle on the situation. Carb problems...needle and seat, or choke would be 2 causes of too much fuel...but i know of one thing that is being over looked here. Correct me if i am wrong but doesnt the fuel pump impulse line run to that particular side of the crankcase? I have seen fuel pumps get pinholes in the diaphrams and leak fuel internally through that line and into the crankcase causing a rich run condition in that particular cylinder. This type of leak can easily foul plugs. Pull the impulse line off the crankcase and check for any signs of wetness inside the hose.
 

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Triumph took words right out of my.. fingers? I had that issues on a 1994 Indy 440 where the fuel pump diaphram got a hole in it and was flooding my magneto side (rope side) cylinder.
 

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Good call Triumph. I did up a older 400 Indy that had the same problem. The 400 even had gas coming out the exhaust. Bad fuel pump. Can be rebuilt pretty cheap. Riley
 

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I've had a similar problem. Turned out to be i accidentally re-installed one of the floats in the float bowl upside down on the shaft, which caused it to somehow consistently foul a plug. I simply flipped the float back over and it ran like a gem.
Just double check to be sure.
 
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