well is one of the plugs wet? he wanted to tow with a little 340 fan? wouldn't be surprised if you blew a cylinder trying to do taht. or is that what he did? whatever that wouldn't surprise me. Snowmobiles don't make the greatest towing machines. In my and most ppl I knows opinion anyway. Do you know how to do a compression test? I would take it to a local dealer and have them compression test it. You will be able to tell if both cylinders aren't right. Take it for a rip if it bobbles and isn't running well then gues what?