I have a question about my 1970s Mercury Thunderbolt ignition 500 50hp motor. Is this dual carb motor suppose to have an air filter/cleaner? Because my carb throats are just wide open without restriction other than the butterflies?
No air filter, just a silentcer cover. It does not get too dusty out on the water.
The device you may have seen on an inboard or I/O that looks somewhat like an air filter is a flame arrester to prevent fires or explosions in the engine compartment. The flame arrester is one of the items on a boat along with PFD's and fire extinguishers that require USCG approval numbers. None required on outboards.
