We took the boat out for a test drive yesterday and the day before. Still running into issues with the port side engine getting over 1600rpm. It appears that the problem may be related to the turbo. Still investigating.

Both engines start really well now. New fuel filters, new hoses, oil change, antifreeze all changed, new starter soleniod, new sensors on the engines and a new turbo cooler on port side.

Our mechanic has some more testing to do, but for now it looks like the turbo on the port side Cummins 5.9L engine may need repair or replacement.