Hey I topped out at 60 mph then ran it through the mud and swamp all day.Then I ran it top speed again and it only reached 48 mph. Anybody know what I should do to correct the problem. Thanks...

 

This may be no help at all but was you vinson caked in mud that may weigh it down. Did any water get in the belt compartment? Are you tires still pumped like they were when you did 60? Soft tires will be slower. Give us a bit more info on what the atv is responding like. Ex. slipping, is it hitting the governer?