It's the only #, it's on the side stenciled. I can't find a cast #.

Question more based on if the older 230 series engine.

That said tho, if engine/parts are genuine g260 Zenoah, cylinder will have ZENOAH cast in side facing coil area and on PTO side left of the 4mm screw mount boss should have a 2075 cast in.

It must be a knockoff... That's not there. It does a letter H inside of a box on the side of the intake port. Anyway, I appreciate you trying to help!!! I value your input. I did put my rpm gauge (for airplane props) on it, and was getting 12,377. It wouldn't be a rocket, but I think it would at least be fun!!!

this is a random question, but how did you link the two engines together? I am working on a twin inline project and can't quiet figure that part out.

You can get Zenoah inline coupler kits from Redline performance marine.