11-01-2018, 06:33 PM
I experienced the symptoms you describe many years ago in my RN fitted with a Ruby speedo, I found that oil was being carried up the cable and getting into the speedo and sticking the revolving disc to the magnet. Or was it revolving magnet to disc? The more oil that got up the more optimistic the reading. About every 5000 miles I cleaned the speedo of oil.