Send me a private message with your e-mail a sthe files are a bit big to post here, you can do that by clicking "message member" at the bottom of this reply.
I'll also copy yhe details from the larger engine which has a separate venturi insert with double taper that went into the inlet hole which you could possibly add to the smaller engine.
Also make sure the non return valve on top of the fuel tank has not picked up so much from the tank and is allowing tehfuel to drain back when it is missing between hits