Go Kart Engines Explained
Today there are many choices for engines on the market. Junked old engines can usually be rehabbed, and new engines that are guaranteed to start easily are widely available locally.
Which Brand to Use?
Since Briggs is the most common engine, most people use a Briggs engine. However, Tecumseh and Honda engines are used quite often. Many people are jumping on the Honda band wagon, as their legendary reliability is a huge plus for generally finicky go karts.
The commercial go kart industry has been hammered lately with law suits and recalls for their products (you can learn more in the links section). Due to liability concerns, B&S no longer markets any of their engines as go kart engines. But of course people were building go karts with Briggs engines far before they marketed that way, and still are. So when you're told at the dealer shop that B&S doesn't make a go kart engine, that's why.
How Much Horse Power Do I Need?
If you're building a smaller kart, a smaller engine in the 3 HP class will suffice, but you'll need to build light and have a light driver. We're going to switch out engines on one of our karts and see how they perform with someone full grown.
But in our opinion, the older 5 HP B&S engine is the classic engine of go karting. With a a 60 tooth sprocket these will go around 20 mph. Today engines are rated a half horse higher.
A large engine 6.5 and above is great for off road karts that need more torque. With larger tires and a heavier frame the extra HP help. But it's easy to get too much speed and not enough low end from a large engine. We're building a 8 HP road kart that will be completed soon, and we'll let you know how it goes, and whether the 60 tooth sprocket is a good match for it.
Horizontal Mount vs Vertical Mount
A go kart engine needs a horizontal mount engine. A horizontal mount engine is what a tiller uses — where the shaft of the motor comes out in the horizontal position.
A lawn mower uses a vertical mount motor, and will need heavy customization (read: lots of money) to be used in a go kart.