Can you use a presure-washer engine 5.5hp honda gasoline-powered for a go-cart?
Yes, anything is possible. For it to be practical the engine must have the output shaft on the side (unlike a lawnmower) and it needs to have some throttle control. Basically you need a centrifigal clutch, some chain and sprockets, some wheels, an axle, a brake (think bike or motorbike) and a frame. And a welder. And time.