SORRY to bother you all again about this engine but --- I still cannot get it to stop surging. I am considering taking it apart and searching for internal problems. I ran a Saito 82 successfully on the same test stand so I know the tank/lines are OK. I have adjusted the regulator extensively 1/4 turn at a time but it still surges. I have examined the fuel line and fuel filter as well. I am wondering if maybe something is trapped somewhere that is causing the surging. Right now I have the needle valve at 2 turns out, and the regulator at 1.5 turns out. I have a new OS 4-stroke glow plug and I am running YS 20/20.

I also noticed that the carburetor will fill up with fuel and overflow slightly after the engine stops. So I will see if taking it apart reveals any blockages.