Go Kart engines are not all the same, there are a number of different options, which means getting the right one can be about doing your homework on things like reliability while balancing the cost factor. Here is a look at some of the things to consider when looking at engines, such as those engines with reverse, and the types.
Go Kart engines fall into two categories, air-cooled and water cooled. Air cooled engines are so called because the engine cooling happens as the kart moves, by the wind or air. Water cooled is so called because water is added to the radiator to help with engine cooling. The more simpler engine is the air-cooled types, they are also smaller and more suited to being a go-kart engine in general. They should not be run in one place for too long though. Water cooled engines can be kept running for longer without overheating risks and they are more heavy duty, but they have to be set up correctly or there will be engine problems.
There are a number of places you can source an engine for a go-kart. They include;
Motorcycles – These are flexible engines and are very easy to use as a go-kart engine because of their flexibility, both the 4 stroke or a 2 stroke would fit.
Snowmobiles – These engines are usually quite easy to find and are not that expensive to buy. While they do have plenty of torque they are not the best engine in hot summer weather.
Lawnmowers – Very easy to find and very affordable. The power is enough to be used in a go-kart but they are slower than other options. They can have too much torque though so the kart can move around.
Cars – In general cars are actually not the best place to find an engine as they are too big and weigh too much. They also are not cheap! There are a few small car engines that could work but it needs extra work to get it to go smoothly.
Leaf Blowers – Small machines like this are a good place to source a small engine for a kart. While they are available they are not cheap though and a clutch is needed.
A quick rundown of other options you have are generators, water pumps, chain saws, other old go-karts, and mopeds.