Just a note for older boat owners. ...

[keokukone]

Just a note for older boat owners.   My 2006 340DA port engine kept stumbling and shutting down to low idle limit.   Replaced the entire cool fuel module,  only to find the paint inside the clean fuel pump side of the module flaked off causing tiny particles to plug the fuel injectors.   Very hard to diagnose people!

[Korkie]

This has been an ongoing thing with the Cool Fuel Modules since they starting using them. Mercury has a service bulletin out on them. Yu need to check and see if your motors have have that service performed. Mercury will supply the parts to fix this, BUT - they must be installed by a Certified Mercury Service person. If you decide to do this, clean all your injectors on both motors, Fuel lines, replace pump housings, fuel filters and filter strainers.

[Grayorg]

I had a similar situation recently - 1999 270DA with 7.4L MPI with cool fuel suystem. It would run erratically at lower RPM and even stall. Long story short, at the advice of another member (Wingless), I checked, among other things, the fuel pressure. I measured 70-75 psi, spec says 43! Changed the fuel pressure regulator and now runs great! Your post makes me wonder if flaking paint caused the demise of my FPR.

[lance]

I had the same problem mercruiser replaced both fuel modules and all my injectors. Definitely look for the service bulletin to see if your covered you will need your engine serial numbers

[keokukone]

Thanks people. Mercruiser volunteered to replace the modules and injectors on both engines. Gonna need to flush the injectors fuel lines too.