We have a 7.4 MPI with Bravo III - About 300 hours on the engine. I've noticed black dirt/soot on the metal fins - I'm suspecting is from the serpentine belt. Question how often do you guys clean the air intake and do you have a magic elixir to use -- I cleaned it last fall with hot water and simple green - blew it out with compressed air

ps the engine runs GREAT-- No issues at all

thanks for the input

Safe Boating

3pointstar

Its best to keep your flame arrestor very clean, try to get rid of all the loose carpet fibers in the engine compartment if you have carpet in that area, make sure your pulley's are rust free and aligned properly to keep belt dust at a minimal. I would wipe as much of the belt dust off first from the throttle plates with a lint free rag with carb cleaner on it then use the card / throttle body cleaner.

I clean mine every fall. Fill a bucket with water/dishwashing soap and let the soak. Brush them off, spray them from the inside out with a hose nozzle and let them air dry in the sun. Our marina has a lot of cotton wood trees, so it is good to clean them at least once a year.

I guess I misunderstood your post the first time around ..

Spray from the inside out with brake cleaner, then use a water hose spraying from the inside out, then compressed air all from the inside out. Let completely dry before reinstalling it.