Hello All, I know nothing about diesel engines. This may be nothing. A friend of mine took his sailboat out yesterday for the first time this season. Small diesel started up fine, ran for 30 min. getting out of marina and into the bay. Then, just like that, the engine revved up to a high RPM. He could not use throttle to reduce RPM, could not get on/off switch to stop the engine, no reaction to anything he tried. He finally disconnected the battery to get it to stop. Any thoughts? It is probably a low horsepower, small size, typical of snailors. Almost sounds like something disconnected. Thoughts? er