Backfiring When First Start-up - Hardcore Sledder

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eldo1978 E OK guys need your help here, I have a 06 Fusion 600 with 230 miles. I purchased with 50 miles last year and noticed when you first start it up and it finally idles with choke off and you take off it tends to bog down and then backfires thru exhaust. I would have to ride it at half choke until the engine reaches around 145-150 degrees before I can turn off choke and than she's fine. I'm wondering is this normal for this sled, is there a fix? Will it get better with more miles on it? I used to own Ski-doo before and never had a problem like this. Any kind of info would be great. Thanks. #1 · Dec 6, 2007 OK guys need your help here, I have a 06 Fusion 600 with 230 miles. I purchased with 50 miles last year and noticed when you first start it up and it finally idles with choke off and you take off it tends to bog down and then backfires thru exhaust. I would have to ride it at half choke until the engine reaches around 145-150 degrees before I can turn off choke and than she's fine. I'm wondering is this normal for this sled, is there a fix? Will it get better with more miles on it? I used to own Ski-doo before and never had a problem like this. Any kind of info would be great. Thanks. Sort by Oldest first Oldest first Newest first Most reactions #2 · Dec 6, 2007 A friend of mine just called last night with a similiar problem on a 95 600 XCR. I suggested he spray the PTO side crank with starting ether to see if rpms picked up at idle. They did indicating a leak at the seal. Not saying that's your problem but it's an easy test #3 · Dec 6, 2007 Carb boots updated? #4 · Dec 6, 2007 check for the carb boot update. also it has some to do with the jetting. The are rich from the factory. lean both jets down one size it helps. not to mention helps throttle response and gas mileage a touch. #5 · Dec 6, 2007 Clean carbs, new plugs, good new fuel and make sure the spark plug wires are on the correct cylinder. It may be starving for fuel and when you choke it that delievers fuel but possible to much which will lead to back firing. dirt or varnished carbs, I clean mine every year just to be sure. #6 · Dec 6, 2007 Sounds like you either have a fuel starvation issue or an air leak. I wouldn't keep riding it like that, or you'll end up burning it down. Check the carb boots...they need to be replaced under a TSB anyway. #7 · Dec 6, 2007 Side note: If sled is stone cold and immediately start up, it will backfire if I try to drive it or move it right away. I let both my sleds warm up to 110-120 coolant temp before i drive off and then drive slow for 5 minutes or so before I get on the hammer. The carb'd sleds are more prone to belching/backfire before warming up. #8 · Dec 6, 2007 The spark plug wires dont matter on a polaris #9 · Dec 7, 2007 Your not letting the sled warm up long enough.You just can't start and go.Like stated above I let it warm up to min 125deg then go if really cold 130. #10 · Dec 7, 2007 Carb boot updates have been done, Sled has 400 main jets and 45 pilot jets also. Now do these sleds have anything like the Ski-Doo sleds in which after so many miles the the computer resets the timing (don't know the exact term it's called) like I said if it warms up then it's good and could ride no problem. #11 · Dec 7, 2007

Carb boot updates have been done, Sled has 400 main jets and 45 pilot jets also. Now do these sleds have anything like the Ski-Doo sleds in which after so many miles the the computer resets the timing (don't know the exact term it's called) like I said if it warms up then it's good and could ride no problem.[/b] Click to expand...

Its what they call a lean pop had a 99 xc 600 did the exact same thing you have to richen up the pilot jets to cure it #12 · Dec 7, 2007

Carb boot updates have been done, Sled has 400 main jets and 45 pilot jets also. Now do these sleds have anything like the Ski-Doo sleds in which after so many miles the the computer resets the timing (don't know the exact term it's called) like I said if it warms up then it's good and could ride no problem.[/b] Click to expand...

Not saying nothing is wrong, but since you mentioned this then I truly believe you are not letting it warm up enough before you drive off. My wifes 600HO has factory jetting and only need choke for a few seconds when cold. If left on longer it will die. Why ? Too rich carb calibration. However, when trying to drive off trailer, move around yard, or etc it will still backfire, bog, etc,etc. It's the nature of the beast with many carb'd anything (cars, boats, etc) because fuel needs to be vaporized when ignitied, but cold surfaces keeps fuel liquid. Now, add into the equation 2 strokes are very sensitive to pipe temperature and whack, bang, pop. You are running leaner than hers, thus why you have to use the choke longer. Cold engines need a ton of fuel to keep running. Now, another huge reason why we need to warm up sleds is cold seizure. Meaning, the engine and it's oil is very cold and this always presents a great opportunity for the engine to seize. Any engine ! So, do your sled a favor and let it warm up. Resist the temptation to get right on it. Start it up, open the hood, check/adjust fluid levels, check drive belt, check storage areas to make sure you have what you want in there, give the suspension and etc a once over. Look at snow underneath for signs of leaks, and then drive off. Just because you haven't had a problem with cold drive offs (seizure) doesn't mean it will never happen if you continue to do this. Insert Quotes Post Reply

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