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Runaway Polaris Trailblazer 250

5K views 6 replies 3 participants last post by  DJV1999 
#1 ·
So I recently picked up a trailblazer 250 that has been sitting atleast 8 years. I cleaned the carb and fired right up( got parked because it got wrecked into a tree and busted the left front steering knuckle) it only ran and revved but had very high idle and bogged only sometimes it idle down enough to get it in gear,and it moved!! So I took the carb apart again, and reset float level and throttle cables,So today I started it up and in a few pulls idled perfect!! Alittle revv and Boggs let it run for 2 min and it clears up and runs great!! BUT HERES WHERE IT GETS WIERD I had it hangin at 3500 ish rpm and let off throttle but...it still hanging a 3500 rpm so I turn the runs switch off and nothing!!! NOW UP too 4500 ish rpm and climbing!!! Then turn key and still nothing!!! And then pull spark plug wire ITS STILL RUNNING AT 5000 rpm!!! 30 sec later I start frantically ripping air box off and cover the carb with my hand and finally it shuts down!!! Wheeew So my question is from sitting so long could the cranks seals go bad?? And or what eels could be the problem? Also I haven't tried to start it since.
 
#2 ·
That would have to be a reallllly hot spark plug to have it keep running once you pulled the wire off.

Apart from the carb what have else have you replaced/cleaned? I'd check compression (should be 110 psi), get a new plug and coil (I think coils are like $15 on eBay), just try and fix the cheap stuff first, eliminate the basics before taking too much apart/spending too much money. Also, maybe a stupid question, but check the throttle cable, make sure that's not gummed up
 
#3 ·
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It has great spark and great compression I actually fixed the front end today it got wrecked by previous owner and I tried to start it and 1 pull started right up,I drove it for 2 min all seemed good?? But I left chocke on. But here's what I found CARB BOOT has many little cracks so need to repalce that is making it run lean?? / making diesel idk but I think I'm gonna put crank seals in it
 
#4 ·
Yeah, you're definitely going to want to replace that carb boot if there are any cracks in it. And I don't think that would explain why it was revving so high but still should be replaced--but you never know. I'm more of the "if it ain't broke don't fix it" when it comes to something like crank seals, so personally that would be the last thing I would do imho, but that's just me
 
#5 ·
when you pulled the plug wire how far away was the boot? if the boot was near the plug the spark could have been jumping to it especialy running at that rpm..
 
#6 ·
Polaris





It was pretty far on the side of the engine plus the key and kills with we're off
 
#7 ·
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Now my new problem is my battery went bad is is going bad and I think I found out why. It started it today and turned headlight on and revved it and it got brighter , then revved alittle more and pop they head light blew out,,,,so I was wondering is that a voltage regulated or something that could have gone bad from sitting for so long ??
 
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