A lawn mower engine is an ideal power source for a go kart because of its size; it provides anywhere between three and five horsepower to propel the kart. Use a horizontal lawn mower engine since it utilizes a horizontal drive shaft that will allow the wheels of the go kart to spin horizontally. A two-stroke lawn mower engine can switch between a vertical and a horizontal drive shaft, but for some engines you may need to turn the carburetor around so it works in the horizontal position.

Placement on the Go Kart

Attach the lawn mower engine to the rear wheel of the go kart using a pulley and drive belt. Set the lawn mower engine above the bearing assembly on a metal plate and align it with the drive pulley. Use bolts to secure the engine in place on the metal plate. The lawn mower engine must always be in contact with the wheel on the rear axle of the go kart in order to move the go kart forward. The lawn mower engine must be mounted so it can move around the wheel to create a variable transmission. Position the wheel near the edges of the metal plate, but close enough to keep it in contact with the lawn mower engine.

The Drive Assembly

Use a chain, sprocket and clutch to build the drive assembly. Mount the clutch to the drive shaft of the lawn mower engine. Mount the sprocket to one of the go kart's rear tires. Use the chain to connect the clutch and the sprocket. The clutch allows the engine to turn at idle. Attach the gas tube to the carburetor. Connect all of the lawn mower engine's electrical connections as they were arranged on the lawnmower. Pull the cord to start the engine. When you use the gas, the chain will turn the sprocket on the rear axle to propel the go kart.

Other Considerations

Do not use a lawn mower engine that is open-cell because oil can leak into the carburetor if the engine tips too far to either side as the go kart is in motion. Use a transmission if you use a lawn mower engine with a vertical drive shaft in a go kart. You will also need to turn the carburetor around to accommodate the horizontal driving functions.

Source:

Go Kart Engines and Motors

Resource:

Background to Wooden Go-Kart Plans

Service Tips for Go Karts and Mini Bikes