A number of 3YM30's have had overheating problems due to undersized heat exchangers and a smaller raw water pump. Yanmar is aware of the issue and have replaced a number of exchangers free of charge. These issues have been showing up around the 150 hour mark on engines with serial numbers lower than 6000
The fix is to install a 66 tube heat exchanger rather than the original 35 tube unit an use a larger raw water pump.
Dirt People Scare me
Last edited by boatpoker; 01-01-2010 at 07:53 PM.