225hp 066 carbon build up problems

[620vs]

I have a 2002 225hp 066. The port side spark plugs and cylinder heads keep getting carbon build up. It goes to the shop, they clean it out with treatment, runs fine for a couple of hours, starts to build up carbon again. It misses and hesitates and loses power when this occurs. It slowly starts at wide open (you can feel a slight miss) and continues to worsen, from take off to full throttle. Anybody have any ideas?

[jb123]

i assume because it has been into a shop that the factory rich oil pump setting has been readjusted to normal ? thats usually done at a 20 hour checkup. look at the oil pump and ensure the linkage at neutral rests on the circular stop pin.

[Ken]

620vs,
If your outboard set up for at least four months without being run, you might consider a carb overhaul - could be gummed up carbs.
Good luck,
Ken K