What is a good compression? The Polaris Service Manual says Service Limit 115 psi.

 

That's exactly right! The service limit is 115 psi which is the lowest "nominal" range that it can usually operate properly,but for only so long! This is not a set in stone range,some start having problems even with a little more compression. Just like your first post on cranking problems,this is one of the indicators and may not be just carb problems.Some would start fouling plugs,some of the others are "it will crank and idle,but bogs down,doesn't have any power" OR "it will crank and run ok for a short while,then die until it cools off and will crank again " The cylinder expands and the rings loose force against it and loose compression and dies. If you wait too long before you address this you can break piston skirts,damage cylinders beyond repair,etc. The average compression reading on a new piston and cylinder bore should be close to 145 psi or more.

 

Tonight I took the carb off and did a partial rebuild. I just changed out the pilot and main jets. I'll do a complete cleaning as I have time. It does seem to idle better and has a bit less trouble getting going but still need to be accelerated gently. Once the revs build though it moves quite well.