Hi Bill, see my reply to you on the LOC site. Checking to see if the shaft is turning is a start but will only tell you that shaft is being driven. I had similar symptoms with my 31, it turned out to be a sheared drive pin on the impeller, a very easy fix, but I had to take it apart to diagnose it..the shaft was spinning merrily away but the impeller wasn't impelling. I also easily diagnosed the lack of circulation by feeling the radiator tanks, the top tank was hot, the bottom not, so no circulation. I then checked the flow of the radiator and engine with a garden hose, this narrowed it down to the pump. Just for the heck of it I also removed the gauge and sender, stuck the business end in a pot of water with a candy thermometer and boiled it to check the calibration, it was spot on 82 years after being manufactured. Email me direct if you need more details, you have my address Blue skies, Tom