I have a couple of these engines , a 46SF with the PD04 pump and a 46VF also with the PD04 pump. Mounting the pump can be a hassle, instructions are still available on the net! The carb is a type 7L for the OS 61 but with a smaller bore. You'll be able to see 46 stamped on the carb.The engine works best with a pipe. Power was extremely good. In those days you could buy the pump and carb combo to upgrade your engine. I haven't checked but if I remember, the carb bore and the hanno carb bore was very close.This engine was designed for the Japanese F3A for 40 sized planes. Ahhh memories!