Been having some troubles with my tired old 25 Kohler. It's been sitting all winter so this afternoon I put a valve cover gasket on it and air up the tires..........get her cranked and let it run for a while. Started to get dark so as I was checking for oil leaks and other problems I noticed the tailpipe on the right side was glowing red......the left side was not as bad, barely noticeable. The reason I parked it was because it was losing power............get in some heavy stuff and it would almost quit. I've had a head gasket replaced recently, a new muffler, new plugs...........and the shop I take it to says the compression is good on both sides. Where should I start looking for problems? Could it be that the head gasket has blown again?