As I have 1999 polaris scrambler 500 4x4. I have been working on it for a while and was finally ready to fire it yesterday, pit bass in the tank and pulled it over a dozen times. I looked where the exhaust pipe goes out and found gas leaking out. Any ideas as to what is wrong? How to fix it? Keep in mind this hasn't been run in probably 5 years in advance

 

Carb needle and seat either worn or sticking allowing too much fuel in the engine. Carb kit should fix the problem.http://www.ebay.com/itm/CARB-REBUILD-REPAIR-KIT-POLARIS-SCRAMBLER-500-98-99-00-01-02-2WD-4WD-2X2-4X4-/230835298722?pt=Motors_ATV_Parts_Accessories&hash=item35bedb21a2&vxp=mtr

 

So you don't think it would be a stuck valve or cracked pistion?

 

Could be any number of things causing raw fuel to pour out of the exhaust,but carb problems would in most cases be the main thing to check.You can also do a compression test if you wish,but with the compression release built into this cam,expect compression to only be within the 55-100 psi range compared to other engines of this size to be around 155-175 psi on average. Also this model was in the general group where cam failures could happen. Not all were affected,but quite a few were. You can pull the cam cover and visibly check the cam lobes especially the exhaust lobe and check/adjust the rocker arms for correct clearance. .006 intake and exhaust. If an exhaust lobe is really worn and if the carb,ignition are okay,usually they will idle good,but bog down,back fire with any amount of throttle.Here's a pic of what a worn one looks like. Bad Cam Pic - ATVConnection.com ATV Enthusiast Community Hope this helps to find the problem.

 

Alright. Thank you so much for the help I'll report back once I have done these things