Air intake silencer

Claim 2

In a marine propulsion unit having a powerhead with a plurality of cylinders, each of said cylinders having a piston and a carburetor with an air inlet, the improvement comprising means defining an air induction passage including an air supply chamber which communicates with said carburetor air inlets and with the atmosphere and which has a volume greater than the displacement of one piston so that the air requirements for one stroke of one of said cylinders can be satisfied by the air contained within said chamber.

Claim 3

A marine propulsion unit having a powerhead with a plurality of cylinders, each of said cylinders having a piston and a carburetor with an air inlet, means defining an air induction passage including an air supply chamber communicating with the atmosphere and having a volume greater than the displacement of one piston so that the air requirements for one stroke of one of said cylinders can be satisfied by the air contained within said chamber, and a connecting passage communicating between said air supply chamber and said carburetor air inlets and having a length equal to the length of said air supply chamber, said air supply chamber being open along its full length to said connecting passage.

Claim 4

A marine propulsion unit having a powerhead with a plurality of cylinders, each of said cylinders having a piston and a carburetor with an air inlet, means defining an air induction passage including an air supply chamber communicating with the atmosphere and having a volume greater than the displacement of one piston so that the air requirements for one stroke of one of said cylinders can be satisfied by the air contained within said chamber, and a connecting passage communicating between said air supply chamber and said carburetor air inlets and having a length equal to the length of said air supply chamber, said air supply chamber being open along its full length to said connecting passage.

Claim 5

A marine propulsion unit in accordance with claim 2 wherein said connecting passage is defined, in part, by a wall in opposed spaced relation from said carburetor air inlets, said wall being covered on the side adjacent said inlets with a noise absorbing pad, and wherein pressure waves emitted from said air inlets and said air supply chamber are directed against said pad.

Claim 6

A marine propulsion unit in accordance with claim 1 wherein said air supply chamber has a volume greater than the displacement of all the pistons.

Claim 7

A marine propulsion unit in accordance with claim 1 including an air inlet passage communicating between said air supply passage and the atmosphere, said air inlet passage defining a tortuous flow path.

Claim 8

The combination of a marine propulsion unit having a powerhead with a plurality of cylinders, each of said cylinders having a piston and a carburetor air inlet and a housing connected to said powerhead, said housing having a first wall, a second wall connected to said first wall, a third wall connected to said second wall and spaced from said first wall, a fourth wall connected to said first wall along a line spaced from the connection of said first wall and said second wall, said fourth wall extending over said carburetor inlets and having apertures receiving said inlets, an out-turned flange extending along three margins of said fourth wall, a top wall connected to said first, second and third walls at the upper margins thereof, a partition in opposed spaced relation to said top wall and connected to said first, second and third walls and extending transversely therefrom, an intermediate bottom wall in opposed spaced relation to said partition, said intermediate bottom wall being connected to said fiRst and third walls, said top wall and said intermediate bottom wall and said third wall having margins coplanar with the margin of said flange on said fourth wall to form a continuous edge, and a cover in engagement with said margins of said housing walls and said flange to form both an elongate supply chamber and an elongated connecting passage communicating with said supply chamber and said carburetor inlets.

Claim 9

The combination of a marine propulsion unit having a powerhead with a plurality of cylinders, each of said cylinders having a piston and a carburetor air inlet and a housing connected to said powerhead, said housing having a first wall, a second wall connected to said first wall, a third wall connected to said second wall and spaced from said first wall, a fourth wall connected to said first wall along a line spaced from the connection of said first wall and said second wall, said fourth wall extending over said carburetor inlets and having apertures receiving said inlets, an out-turned flange extending along three margins of said fourth wall, a top wall connected to said first, second and third walls at the upper margins thereof, a partition in opposed spaced relation to said top wall and connected to said first, second and third walls and extending transversely therefrom, an intermediate bottom wall in opposed spaced relation to said partition, said intermediate bottom wall being connected to said fiRst and third walls, said top wall and said intermediate bottom wall and said third wall having margins coplanar with the margin of said flange on said fourth wall to form a continuous edge, and a cover in engagement with said margins of said housing walls and said flange to form both an elongate supply chamber and an elongated connecting passage communicating with said supply chamber and said carburetor inlets.

Claim 10

The marine propulsion unit of claim 6 including lower sidewall portions of said first and third walls, a bottom wall connecting said lower sidewall portions and spaced from said intermediate bottom wall, an air inlet in said bottom wall, and a second housing connected to said lower sidewall portion, said partition and said intermediate bottom wall to form an air inlet passage connecting said air inlet with said air supply chamber.

Claim 11

The marine propulsion unit of claim 6 including a cowling which is spaced from and surrounds a portion of said powerhead and wherein said first, second and third walls of said air induction passage are located adjacent the side of said powerhead between the powerhead and said cowling.

Claim 12

The improvement of claim 7 including a plurality of apertures in said lower side walls to afford communication of said inlet passage with the area between said cowling said powerhead.

Claim 13

In a marine propulsion unit including an engine powerhead with a plurality of cylinders, each of said cylinders having a carburetor air inlet, the improvement comprising means defining an air induction passage for supplying air to said cylinders, said passage having an air inlet in communication with the atmosphere, a supply chamber having a volume greater than the volume of any of said cylinders and being connected to said carburetor air inlets, and an elongated connecting passage which extends the full length of and communicates with said supply chamber and which has a thickness and volume substantially less than said supply chamber.

Claim 14

In a marine propulsion unit including an engine powerhead with a plurality of cylinders, each of said cylinders having a carburetor air inlet, the improvement comprising means defining an air induction passage for supplying air to said cylinders, said passage having an air inlet in communication with the atmosphere, a supply chamber having a volume greater than the volume of any of said cylinders and being connected to said carburetor air inlets, and an elongated connecting passage which extends the full length of and communicates with said supply chamber and which has a thickness and volume substantially less than said supply chamber.