Re: Intake silencers gone missing?

[amuller]

quote Chinewalker:

It was discovered on some models that there was a slight tuning effect with the silencer in place. There is a small standing wave in front of a carburetor while it is running. If that wave can be “bounced” into the carb throat at the right time, it can have a small charging effect, in addition to noise deadening. A friend of mine who was heavy into outboard racing tested this with an Evinrude 15A, using a plate in front of the carb while running on a test wheel. The tach showed about a 50-100 RPM difference depending on placement of the plate. Best placement was about where the carb cover would normally sit in front of the carb.

Yes, I think a properly designed inlet tract should be able to give a power increase as well as quieter operation.

But the OMC plate with fiberglass on it? Is this intended as a reflector, or a partial silencer, or what ???

Is there not also the possibility of that "standing wave" containing fuel, or fuel vapor? I’ve wondered if a possible hazard exists with the carb inlet pretty close to sparking points.