Pulled my Sport out yesterday and noticed that the spark plug had obviously fouled out. So I pull over to the pickup and replaced the bad plug with a new one. Now it will not start. After a couple of crankings, I pull the plug and gas is all over the tip. Anyone have any ideas as to what my problem may be? Thanks.

 

Check to see if you are getting spark at all. If your CDI box is bad, you might just be feeding fuel to a dead spark plug!
My MX 400 Sport

 

if you are getting spark then run a compression test. Brad--------96 425 magnun 4x4,white spring,K&N filter----------96 400 Sportsman green spring,blue driven spring,GBC Gators

 

Did you try the easy things first? I left mine sitting for about 2 months and when I went to start her up it just wouldn't start. Finally after about 5 minutes I pulled the fuel cap off and VRRRROOOOOOM...she fired right up. Must have been vapor locked.

Recently I tried starting after letting it sit for about a month and it wouldn't start. I figured it was the same thing as before, so I took the fuel cap off and thought it would start right up...nope. I finally just got off the stupid thing and pulled one time on the pull cord and it started right up. I didn't think that was the problem because it sounded like it was turning over just fine, but I guess not.

Anyway, good luck.

-Josh

 

Update.

I got a chance to look through the manual and read some info on the web. Here is what I know after last night.


I think it is a carburator setting problem. It did start on the first pull (starter does not work). This is how I knew the plug was fouled. I drove it over to my pick-up to get the new plug, approx. 100 yards. After putting the new plug in, I have been unable to get life out of the machine. The fouled plug was black, somewhat glossy and wet. This tells me that it was running rich (also the way it ran before pulling the plug is indicative of running rich). So, last night I adjusted the air screw according to the shop manual. I was sure that this would fix the problem. After a couple of pulls, it sarted to come to life but alas it still would not start and I'm back to the same place I was before. NO LIFE!

So, I have gas, fire and new plug. The difficulty is not having my starter. Many pulls makes one tired trying to fix a fuel/air mix problem. I think I will fix the starter before adressing the carb problem. Anyone rebuilt a Polaris starter? If anyone has more input on the carb adjustments, I'm all ears!

Thanks

 

If the quad has been sitting awhile check your airfilter may you have a mouse nest in your airbox.

 

Most of the polaris starter problems are in the relay and conections.This my experiances.

 

Got Gas?
Check to make sure the carb has not worked it way out of the rubber carb adapter. Also make sure the rubber carb adapter is not cracked of split, especially on the bottom where goes from round to rectangular.

Got Spark?
If the CDI or Coil are bad, replace them both at the same time, otherwise you can blow the old one when fire it up with the new one.

Got Compression?
You need a minumum of 115 psi for this baby to run.

 

How long did it set around with the old gas in it? If it has sit with gas in it for a while, the pilot jet could be stopped up slightly or something else. Clean the carb and jets out and get fresh gas. Check compression. Check choke adjustment, and oil pump adjustment.