Several message threads on the Trailer Sailor site may be of interest: http://bbs.trailersailor.com/forums/trailersailor/index.cgi/read/345875 http://bbs.trailersailor.com/forums/trailersailor/index.cgi/read/345972 http://bbs.trailersailor.com/forums/trailersailor/index.cgi/read/346183 Symptoms include: Motor was locked up. Gurgling sounds heard when sparkplug was removed. Steve R. M-15 #119 Lexington, KY