RE: OS Max .25 engine
A little rtv is an accepted method, dont go crazy with it though. Let it dry a long time before using the engine, a day maybe?
Idont think the muffler to crankcase fit is all that great on these but if you fuelproof the firewall it should be fine. If you cant find a screw at the local hardware store try Fastenall, they usually have a local outlet. Imight even have one if you need. Hate the cross head screws they use, always strip. I prefer to replace them with Allens.