Trying to trouble shoot an intermitent overheat alarm problem and Clymer manual doesn't provide all the information I want. Trying to determine 1) Normal engine temperature and where measured; 2) Normal water pressure at idle and/or other speeds. Problem occurs after running engine for awhile, shut down for at least 15 minutes, run at 3000 rpm for 1/2 mile or so and engine overheat alarm sounds, shut off engine restart immediately - no alarm and can run from that point on without alarms. Problem will happen everytime I shutdown for at least 15 minutes and always at about the same distance/time from startup. Engine has 110 hrs on it and this issue started about 30 hrs ago (very seldom run at alrm conditions so first few times I didn't think it was an issue since restart cleared the alarm). I have replaced the spark plugs, water pump impeller, thermostats and have ordered both temp sensors to be replaced. Engine runs good and gets good economy, had good water stream before and after impeller change out, spark plugs looked damp (running rich?) when replaced but engine has always started and run well, engine is generally run in fresh water with occasional excursions into saltwater and always flushed after saltwater use. Any ideas from the experts?
