Explorer 400 Not Starting--Help - Polaris ATV Forum
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post #1 of 5 (permalink) Old 10-22-2009, 12:43 PM Thread Starter
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Explorer 400 Not Starting--Help

I recently purchased a 2001 Polaris Explorer 400, which is a two stroke model. It seems to keep flooding out, because everytime that I pull the plug, it is wet. I put the plug in the boot, and put it against the block, and it appears to have good spark. I pulled the carb, and disassembled/cleaned it, although it looked good.

I found the crankcase drainplug, and removed it, just to make sure that crankcase was not full of gas. It had about 4 or 5 oz. in it, so I am assuming that the float stuck at one time, maybe from sitting.

If I put a fresh plug in it, and pull it over (the elec. start is not working right now), it will backfire sometimes. If I choke it, then it will run for just a second or two, but will only start if I give it just a little throttle.

I checked the reeds, and they look to be in good shape. I pulled the reeds, and looked at the piston/cylinder with a flashlight, and the skirts, ports, etc. all look good. I threw a compression gauge on it, and it was at 125psi.

I could pull it over all day, and it just keeps doing the same thing. Can the timing on a two stroke get out of whack? Maybe a partially sheered flywheel key?

I am wondering if anyone knows the stock carb screw adjustments for the idle and air bleed screws?

I checked the fuel delivery, and there is fuel getting to the carb.

If anyone has some ideas, I would love to hear them, as I am ready to throw a flare into the gas tank. lol

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post #2 of 5 (permalink) Old 10-22-2009, 02:41 PM
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First off, welcome to the board!

I tried setting my password to "penis" but it said my password wasn't long enough...
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post #3 of 5 (permalink) Old 11-09-2009, 06:49 PM
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same problem

I was hoping to here a response on your post i am having the same issue with a 96 explorer
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post #4 of 5 (permalink) Old 11-09-2009, 07:40 PM Thread Starter
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Explorer Starting


I found out the problem with the wheeler, which was interesting. The clutch had not been serviced by the previous owner, and needed some attention. This caused the flywheel key to partially sheer, which put the timing out of whack. Serviced the clutch, installed a good used flywheel, along with a new key, and it runs like new. I did not have the appropriate flywheel puller, so I had a shop pull it for me. Just make sure to give the flywheel a good inspection, as the keyway sometimes looks ok, but some material may have been ground away from the flywheel spinning on the crank. This lessens the depth of the keyway, and makes them more prone to shearing the key.

Hopefully this helps, and good luck.

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post #5 of 5 (permalink) Old 11-28-2009, 02:33 PM
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Bump anyone else have any ideas? I am having a similar problem. Compression is at 110. Been through the carb about three times. Good spark. Pulled the flywheel off tonight. Flywheel key is intact and the flywheel was lined up with it when it was pulled. I have no idea where to go with this.
Oh and the atv is a 1995 400 4x4
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