Re: What do air silencers do? (Just curious)
The reed valves on two-stroke motors can make a lot of noise as they open and slap shut. The silencer muffles it. Your 33 does not have one because the fiberglass hood is the silencer. It also has a silencer pad where the air enters the lower cover (pan). Yeah, yeah, I know, the 10 has a fiberglass hood too. It took the engineers a couple of years to figure out the sound control without a silencer (saves money).
On more sofisticated motors with exhaust tuning, the silencer is part of the tuning, sound waves actually acting as a sort of supercharger. That is why some motors suffer a performance loss without the silencer.
Not only that, the airflow through the silencer figures into the fuel/air mixture which is controlled by fixed carburetor jets. Upset the air volume without compensating with jet size and you upset the mixture.