Did Paul give us the definitive guide on how to hot start an airplane? Try his technique and see what you think. Also, unnecessary cylinder removals, a faulty tach, and a letter writer and guest who question if burping is safe. Send your questions to [email protected] for a chance to be on the show. Full notes below: Walt has a Seneca and has had to replace three cylinders in the last five years. He’s concerned that his mechanic caused the problem after hammering on his exhaust to remove it. The hosts don’t think the incidents are related. While it’s not usually a good idea to hammer on the exhaust, they think it could be useful and safe in limited circumstances. Mike hones in on the reason for the cylinder replacement, and encourages Walt to be more suspect of the need to replace the cylinders in the future. Tim thinks his tach is off. He has an alternative device that also reads rpm that shows a different value, so he’s wondering what he can do to adjust or fix his tach. Paul said the tach is technically adjustable, but being an instrument, it’s not something an owner or even most mechanics can do. Unfortunately the hosts agree it’s time to replace it. Luke operates a few Extra aerobatic airplanes, and he constantly struggles with hot starts. He has been resorting to blowing large fans up through the cowling, but that’s not always practical. In a Continental it’s recommended to run the fuel pump for about two minutes to purge the hot, boiled off fuel and flush the system with cold fuel. Paul said his technique works on Lycomings and Continentals. Start with everything forward with the pump on. Then listen, and as soon as the flow stabilizes and sounds like it’s pumping liquid, you’re done. Mixture and throttle back, but keep the pump on. Crack the throttle, engage the starter, and then advance the mixture control over a few seconds. Thomas has a Mooney and he tried the burping procedure from a recent episode. But the next flight his attitude indicator didn’t come online, and he heard that turning the prop backward can ruin the vacuum pump. The hosts have all heard this concern as well, but Mike’s never heard a confirmed case that turning the prop backward causing a failure. Regardless, this seems to be an issue with older styles of pumps.