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Discussion Starter #1
I have a 91 Polaris Trail Boss (4x4) that I just recently put a new piston in. I bought it from a fellow who didn't know what he was doing and he broke a piston when he was trying to put a new one in. The compression is back up again with a new piston installed. Everything runs great, except it likes to bog down when you first warm up the engine. Its fine while its cold, and runs okay after getting the engine hot (maybe after about 25-30 min). It will also run okay if you keep the engine reved up high, but if you slow down to change to reverse, a sandy/rough spot, or let it idle for a bit, then it gets into this rut where it just sits and idles. It wont completely die, but it bogs out if you try to give it gas. I have found that if it gets into this bogging rut and I push the starter switch (with the engine running) it will snap out and start running as long as you don't let the rpm go to low. I'm afraid I'm ruining my starter though. Hopefully someone out there can help me with this. I tried to explain it as best I could. Thanks!
 

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Ok,it sounds like the needle adjustment in your carb. In the slide is the needle,in the needle are 3-5 slots for a clip to go in.The clip is usually in the middle slot. Drop it one groove to richen the midrange. Should fix it.
 

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Working again on the 250 Polaris Trialboss (4x4)

I'm back again working on this same four wheeler as I mentioned above, and guess what…still the same problem. Symptoms are similar as I mentioned back in 2012. As I guessed, my starter is failing from having to push the button when the 250 polaris starts bogging out. Several interesting facts to add though. First, I forgot to mention that it backfires as well as bogs out. Second, for whatever reason this whole problem went away during the winter when it was colder. I live in the New Mexico desert so it doesn't stay super cold the whole time, but we can easily get down to single digit degrees (yes Fahrenheit). The summers here are hot and dry though, and that is when the problem has now resumed. I was told this could be a jetting issue, so i got two jets, each a size lower, and have played around with the carb. I've adjusted jets, air/fuel screw, the needle, everything i can think of, but nothing really effected it. Now for my third discovery. Up til yesterday, I definitely thought it was a carb issue. To make a long story short, I took the battery out, and it stopped bogging out on me! At least for a short drive, it ran fine. However, when i turned on the four wheel drive button, it started bogging out again in similar fashion. So now i have a feeling that it is an electrical problem.

Anyone with some helpful ideas? I'd appreciate any advice, cause this thing is driving me nuts!! Thanks.
 
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