Tamper resistant adjustment valve for a charge forming device

1. A valve for a charge forming device, comprising:

a needle having a first end and a second end;

a valve body having an axis extending between a first end and a second end, a cavity open to the second end and in which part of the needle is received with the second end of the needle extending out of the second end of the valve body; and

a projection extending axially from the first end of the valve body to a free end of the projection, and the valve body has at least one drive surface axially spaced from the free end of the projection, the drive surface extends axially and radially and the projection is intersected by the axis.

2. The valve of claim 1 wherein the projection is defined by the needle and the first end of the needle defines the free end of the projection.

3. The valve of claim 1 wherein the projection is coaxial with the valve body.

4. The valve of claim 1 wherein the at least one drive surface includes at least two drive surfaces that are defined on opposite sides of the projection.

5. The valve of claim 4 wherein the drive surfaces define at least part of a slot formed in the first end of the valve body.

6. The valve of claim 5 wherein the drive surfaces face inwardly toward axis.

7. A valve for a charge forming device, comprising:

a needle having a first end and a second end;

a valve body having an axis extending between a first end and a second end, a cavity open to the second end and in which part of the needle is received with the second end of the needle extending out of the second end of the valve body; and

a projection extending axially from the first end of the valve body to a free end of the projection, and the valve body has at least one drive surface axially spaced from the free end of the projection, the drive surface extends axially and radially, wherein the at least one drive surface includes at least two drive surfaces that are defined on opposite sides of the projection and wherein the drive surfaces face outwardly away from the axis.

8. The valve of claim 7 wherein the drive surfaces extend radially beyond the projection.

9. The valve of claim 8 wherein the needle defines the projection and the first end of the needle defines the free end of the needle.

10. A valve for a charge forming device, comprising:

a needle having a first end and a second end;

a valve body having an axis extending between a first end and a second end, a cavity open to the second end and in which part of the needle is received with the second end of the needle extending out of the second end of the valve body; and

a projection extending axially from the first end of the valve body to a free end of the projection, and the valve body has at least one drive surface axially spaced from the free end of the projection, the drive surface extends axially and radially and wherein a portion of the exterior of the valve body is threaded.

11. The valve of claim 10 wherein the valve body includes a drive portion that extends axially from the threaded portion of the valve body.

12. A tool for rotating a valve that has a projection extending axially beyond a drive surface to be engaged by the tool, the tool comprising:

a body having an axis, one or more driving surfaces and a cavity formed in the body, the cavity extending axially into the body between the driving surfaces and arranged to receive at least part of the projection, the driving surfaces extending axially and radially and arranged to engage a surface of a valve upon rotation of the tool.

13. The tool of claim 12 wherein the driving surfaces face outwardly, away from the axis.

14. The tool of claim 12 wherein the driving surfaces face inwardly, toward from the axis.

15. The tool of claim 12 wherein the driving surfaces are arranged on opposite sides of the cavity.

16. The tool of claim 12 wherein the body includes a pair of fingers with the cavity extending between the fingers, and with the driving surfaces defined by the fingers.

17. The tool of claim 16 wherein the axis extends between the fingers and the driving surfaces are parallel to the axis.

18. The tool of claim 16 wherein the cavity defines part of the fingers.

19. A rotary throttle valve carburetor, comprising:

a body defining a fuel and air mixing passage, a throttle valve chamber communicating with the fuel and air mixing passage and a fuel flow path communicating a supply of fuel with the fuel and air mixing passage;

a throttle valve rotatably and axially movably received in the throttle valve chamber and including a throttle valve passage variably aligned with the fuel and air mixing passage; and

an adjustment valve threadedly carried by the carburetor in communication with the fuel flow path to restrict fuel flow through at least a portion of the fuel flow path in at least one position of the throttle valve, the adjustment valve having a valve body with a threaded portion, at least one drive surface that defines a first engagement portion and a second engagement portion radially spaced from the first engagement portion, the adjustment valve also having a needle carried by the valve body for movement with the valve body, and the adjustment valve having a projection extending axially from an end of the valve body and axially beyond the at least one drive surface.

20. The carburetor of claim 19 wherein the throttle valve defines a cavity in which the valve body is received so that the at least one drive surface is located within the cavity and is surrounded by a body of the throttle valve.