I recently bought a 1994 pro vxr 61x single carb waverunner. The first time I took it out it ran great. It idles fine but the engine tach jumps around. The main reason for this post is that after about 20 minutes the ski feels like it is starving, it smokes a whole lot. When I give it gas it hesitates and will not go full throttle. If it is too lean would this be a problem. What type of gas should be run? What would the ski do if the temp switch was bad. How do I check the compression. Any advise or recommendations would be greatly appreciated.