1998 polaris sport 400 runs well but floods when it sits - ATVConnection.com ATV Enthusiast Community



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Old 02-11-2017, 11:54 PM
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Default 1998 polaris sport 400 runs well but floods when it sits

So i finally got a chance to ride my Sport, ran like a dream. But after i let it sit, it flooded. I turn the gas off all the time, am i supposed to run it until the gas in the carb is dry? I also took a look at the vent lines, they where plugged so i replaced them, could that be part of the issue to?

any feedback would be appreciated.
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Old 02-12-2017, 03:56 AM
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If you still have the "tee",throw it away and have a separate drain/over flow line at the carb bowl,run new carb vent lines up,zip tie them to the choke cable or throttle cable and let them drop in the space between the tank support bracket and the tank itself. Check that when you turn the valve off,fuel flow stops. Could be partially a valve problem if it's leaking,but the most common problem is a worn needle and seat allowing fuel into the engine.A good rebuild kit can solve that. 1998 Polaris SPORT 400L (W98BA38C) Carburetor Sport 400L | Cycle Parts Warehouse Plus here's a couple videos on this carb.
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Old 02-12-2017, 10:03 AM
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Just rebuilt the carb on it but now it wont start at all. I pulled the vent lines and tied them to the choke cable, i think im going to pull the carb and just rebuild it.
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Old 02-12-2017, 11:32 AM
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Cleaning a carb doesn't always help if parts are worn. Needle and seat is usually the main problem,plus make sure the float arm is level with the carb body after you replace any parts.If it's off,the float arm tang can be slightly bent to correct.
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Old 02-12-2017, 04:01 PM
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I got it running - pulled the spark plug and let it dry out because it was wet fouled. When i parked it, i let it run out of gas in the carb so it wouldnt flood and turned the gas off. Im going to take a look at the carb at some point. Are you supposed to turn the gas off on this atv? I normally dont turn the gas off on my xplorer 400.
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Old 02-12-2017, 04:45 PM
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It's a good idea to turn the fuel valve off on any machine when you get through riding especially these old Polaris 2 strokes. The thing is that even with the fuel valve on there shouldn't be gas getting into the engine. If it is,usually a worn needle and seat isn't stopping fuel flow and possibly the float level may be off also.Again check that the fuel valve works properly. At least replace the needle and seat(needle valve assembly) and a new bowl gasket."IF" the float arm is worn and wobbly,replace it also along with the float pin. The float arm can hang up and cause flooding if really worn.If it's ok,just make sure it's level with the top of the float bowl. Make sure the carb vent tubes are clear and open also.Look at the videos for tips if needed. Or you can look at this pdf section from the manual on carbs.Shows how to set the float level along with rebuilding.You have the VM 34 Mikuni. https://www.google.com/url?sa=t&rct=...U2gGlaHJWSIlbA
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Old 02-16-2017, 09:41 PM
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I fried the starter a few days back, I will check for that when I replace the starter. I was wondering how much work and headache it would be if I where to replace the piston.

And thanks again.
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Old 02-17-2017, 12:00 PM
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Again if you haven't at least replaced the needle and seat,this can be the main problem.This service manual can pay for itself on service and repairs. https://www.tradebit.com/filedetail....pair-1996-1998
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Old 02-20-2017, 07:33 PM
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Will a carb rebuild kit come with a needle and seat? And what would be the best brand to rebuild it?
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Old 02-21-2017, 05:30 AM
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Can't find a Shindy kit for this models,but this seems to be ok. Always check the jets in kits to be sure they're the same size as the oem ones.CARB REBUILD REPAIR KIT POLARIS 1998 - 1999 SPORT 400 2WD 2X4 98 99 | eBay
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