[C320-list] Yanmar starting problem

[Robert Dean]

I have hull 550, it's a 1998 with a Yanmar 3GM30. Last fall it became hard to start after it sat for a few days. Once it started it ran a little rough for a minute or two than ran fine. After it ran it would start with just the touch of the starter button.If it sat for a few hours it would still start right up. It is getting air in the fuel lines some how.Over the winter I did away with the check valve on the fuel line at the injector pump per Yanmar service advisory 11-1-2000.  I replaced the Racor filter element and gaskets and the Yanmar filter element and o-ring. I replaced the fuel hose from the tank to the Racor  and from Racor to the lift pump,I also replaced the line that goes around the dipstick. I replace all the copper seals.Everything is new from the fuel tank to injector pump,but I still have the same problem. I had a mechanic look at it,he couldn't find any leaks. The mechanic did say it might be an injector leaking. Before I go to the expense of replacing injectors, I thought  I would ask if anyone else had this problem.
Bob DeanJust Chillin 550Worton Creek