General purpose engine

1. A general purpose engine which comprises:

a cooling fan fixed to an engine rotary shaft;

a muffler to silence exhaust gases;

a muffler covering to cover the muffler; and

an auto choke device to control an opening of a choke valve in an air intake passage by the utilization of heat evolved from the muffler, wherein

the auto choke device comprises:

a drive source, which is fitted to the muffler covering in a non-contact fashion to the muffler and exposed to an outer surface of the muffler covering; and

a link member to connect between the drive source and the choke valve,

the drive source includes a bracket fitted to the muffler covering and a bimetal fitted inside the bracket, the bimetal being laterally disposed between the muffler and the muffler covering, and

the bracket includes a heat shield extending towards an inner side of the muffler covering and configured to block out a cooling wind then flowing towards the bimetal.

2. The general purpose engine as claimed in claim 1 , wherein the bracket is fastened removably to the muffler covering by a fastener in a condition that the bracket is exposed from the outer surface of the muffler covering.

3. The general purpose engine as claimed in claim 1 , wherein

the bimetal and the link member are rotatably connected together by means of a link lever, and

the link member is engaged with the link lever.

4. The general purpose engine as claimed in claim 1 , wherein the heat shield extends towards a gap between the muffler and a cylinder head.

5. The general purpose engine as claimed in claim 4 , wherein the heat shield is configured to guide the cooling wind towards a point of connection between the muffler and the cylinder head.

6. The general purpose engine as claimed in claim 1 , wherein the engine rotary shaft extends in a vertical direction.

7. The general purpose engine as claimed in claim 6 , further comprising a fan covering configured to cover an upper surface of the engine, which fan covering is made of resin material.

8. The general purpose engine as claimed in claim 1 , the drive source is detachably fitted to a surface of the muffler covering lying along a plane that intersects with an axis of the engine rotary shaft.

9. The general purpose engine as claimed in claim 8 , further comprising a fan covering configured to cover the engine from one side of an axial direction of the engine rotary shaft, wherein

the drive source is detachably fitted to a surface of the muffler covering, which surface is directed to the one side of the axial direction of the engine rotary shaft.