I built this with a 420cc engine and a pump – it really works

My workshop’s electrical system has some limitations – running multiple machines at once makes it hard to power a large air compressor. That’s why I decided to build a powerful and mobile gas-powered air compressor, ready to supply extra air whenever I need it – and usable even without electricity. Originally, I planned to use a 3090 compressor pump, but I was concerned the centrifugal clutch might slip under heavy load. So I started with a 2090 pump, rated for about 500–600 L/min. The engine is a 420cc gas engine, chosen because a 200cc engine had trouble handling pumps with 2×65 mm cylinders in my past experience. I mounted an 80 mm centrifugal clutch, which, combined with the pulley on the pump, results in approximately 940 RPM on the pump shaft. Throttle control is handled by a 12V linear solenoid (3 kg pulling force) connected to a standard 400V pressure switch normally used with three-phase air compressors.