If you have used a gasoline powered push lawn mower, you have already operated a vertical shaft motor. Due to the relative availability of old vertical shaft motors, they make an economical choice for a home go kart power source. But, anyone who has ever built or tried to build a go-kart with a lawnmower engine has faced a fundamental mechanical problem. The vertical rotation of the motor must be converted to horizontal rotation to turn the go-kart wheels. This is not as simple as turning the engine on its side, as the carburetion techniques of almost all lawnmower engines do not allow operation in anything other than the upright position. This article will explain some ways to use a vertical motor for karts.

The pioneers of the outboard motor industry also had to tackle the problem of transferring vertical rotation to horizontal rotation. A solution to the problem of how to use a vertical motor for karts takes out a page on the construction of outboard motors. In an outboard motor, the vertical motor turns a shaft that turns bevel gears attached to the propeller shaft. The key is the use of bevel gears, a set of gears designed to transfer rotational power at a defined angle and thus transfer vertical rotation to horizontal rotation. A go-kart builder would be lucky enough to have at his disposal bevel gears recovered from an old outboard motor to implement in the kart design.

A simpler solution to the problem involves the use of a simple belt and pulley system. The go-kart builder would attach pulleys to the driveshaft of the vertical motors and to the axle of the kart. Then a belt would be attached to both pulleys. Vertical rotation is transferred to horizontal rotation through a twist on the belt. Unfortunately, this method of how to use a vertical go-kart motor is not that reliable. The belt could slip and break as most belts are not designed to twist while in motion.

This article explains two methods of using a lawnmower motor in building a go kart. Surely there are several other methods to solve the vertical to horizontal rotation engineering problem, but these two methods would be the most economical and practical for a home hobbyist. The use of bevel gears in kart construction is more reliable as long as the construction is accurate, but the construction is more complicated and expensive. The twisted belt and pulley method is easy and inexpensive, but not really reliable. It is up to the kart builder to determine which method they would prefer to use.