Automatic engine decompression system for two-cycle engine

Claim 2

An internal combustion engine comprising an engine block defining an engine cylinder having a port, a crankshaft rotatably supported by said engine block, a valve movable to and from a position closing said port, means biasing said valve toward said position closing said port, an engine starter mechanism including a rotary element and a member operably associated with said rotary element and movable relative thereto and to and from a position in driving connection between said crankshaft and said rotary element to facilitate starting of the engine, and a linkage mounted on a part fixed with respect to said engine block and being operably engageable with said member and said valve to displace said valve from said port closing position against the action of said biasing means in response to movement of said member to said position of driving connection, whereby to permit gas flow relative to said cylinder through said port.

Claim 3

An internal combustion engine in accordance with claim 1 wherein said engine block includes a recess and a passageway between said recess and said cylinder adjacent the head end thereof and wherein the engine further includes a plug threadedly received in said recess and including a bore communicating with said passageway, a first counterbore extending from said bore, a second counterbore extending from said first counterbore, said first and second counterbores defining a valve seat, and a radial bore extending from said first counterbore and communicating with the atmosphere.

Claim 4

An internal combustion engine in accordance with claim 2 wherein said valve comprises a stem movable in said bore in said plug and a valve part engageable with said seat.

Claim 5

An internal combustion engine in accordance with claim 3 wherein said means for biasing said valve toward said position closing said port includes a collar on said stem located exteriorly of said bore and a spring in surrounding relation to said stem and seated against said collar and said plug.

Claim 6

An internal combustion engine in accordance with claim 1 wherein said linkage comprises a link pivotally mounted about an axis which is fixed relative to said engine block and which extends perpendicularly to the direction of valve movement, said link including a portion engageable with said valve to effect port opening movement of said valve in response to movement of said member to said position of driving connection.

Claim 7

An internal combustion engine in accordance with claim 5 and further including spring means resiliently biasing said link away from engagement with said valve.

Claim 8

An internal combustion engine in accordance with claim 6 wherein said spring means also serves to bias said member away from the position of driving connection.

Claim 9

An internal combustion engine in accordance with claim 1 wherein said means biasing said valve toward said position closing said port also serves to urge said linkage so as to urge said member away from said pOsition of driving connection.

Claim 10

An internal combustion engine comprising an engine block defining an engine cylinder having a port, a crankshaft rotatably supported by said engine block, a valve movable to and from a position closing said port, means biasing said valve toward said position closing said port, a pull rope starter including a rotatably mounted pulley with a hub extending axially therefrom, and a pinion carried on said hub for movement to and from a position in driving connection with said crankshaft to facilitate starting of the engine, said hub and said pinion including means affording movement of said pinion to said position in driving connection with said crankshaft in response to rotation of said pulley, and a linkage mounted on a part fixed with respect to said engine block, said linkage including means connecting said pinion to said valve to displace said valve from said port closing position against the action of said biasing means in response to movement of said pinion to said position in driving connection with said crankshaft.

Claim 11

An internal combustion engine comprising an engine block defining an engine cylinder having a port, a crankshaft rotatably supported by said engine block, a valve movable to and from a position closing said port, means biasing said valve toward said position closing said port, a pull rope starter including a rotatably mounted pulley with a hub extending axially therefrom, and a pinion carried on said hub for movement to and from a position in driving connection with said crankshaft to facilitate starting of the engine, said hub and said pinion including means affording movement of said pinion to said position in driving connection with said crankshaft in response to rotation of said pulley, and a linkage mounted on a part fixed with respect to said engine block, said linkage including means connecting said pinion to said valve to displace said valve from said port closing position against the action of said biasing means in response to movement of said pinion to said position in driving connection with said crankshaft.

Claim 12

An internal combustion engine in accordance with claim 9 wherein said engine block includes a recess and a passageway between said recess and said cylinder adjacent the head end thereof and wherein the engine further includes a plug threadedly received in said recess and including a bore communicating with said passageway, a first counterbore extending from said bore, a second counterbore extending from said first counterbore, said first and second counterbores defining a valve seat, and a radial bore extending from said first counterbore and communicating with the atmosphere.

Claim 13

An internal combustion engine in accordance with claim 9 wherein said linkage comprises a link pivotally mounted about an axis which is fixed relative to said engine block and which extends perpendicularly to the direction of valve movement, said link including a portion engageable with said valve to effect port opening movement of said valve in response to movement of said member to said position in driving connection with said crankshaft.

Claim 14

An internal combustion engine in accordance with claim 11 and further including spring means resiliently biasing said link away from engagement with said valve.

Claim 15

An internal combustion engine in accordance with claim 9 wherein said means biasing said valve toward said position closing said port also serves to urge said linkage so as to urge said member away from said position in driving connection with said crankshaft.