How to do a compression test on an outboard engine. This is usually done when you’re buying a used engine, or you’re trying to diagnose a loss of power, valve issue, rough idle, or just to rule things out. We don’t have to do it a lot, but we recently sold 3 sets of working engines, and are just verifying their condition for the buyer. It’s basically the same process for a vehicle. #howto #mechanic #outboard #engine #boating | Captain Retriever