rev,
I didn't weigh the engine without the muffler. It's about 4# as is with the firewall mount that I made from aircraft ply. I'll be using the stock muffler with a pipe braized on to go out the bottom. I haven't opened up the muffler to see what's inside. If there's any baffles I'll remove them. I can use the stock muffler cuz there's tons of room inside the cowl. I'm using the engine in a BUSA Fokker Tripe. I ran it on the test stand with an 18-6 prop, but I'm hoping I can use a 20-6 eventually. If the plane comes in at 14# or so this engine should haul it pretty well since they fly well with a G23. I want to put in a smoke system and do some aerobatics with it.

I ran it with the prime bulb removed and the hole plugged. I closed the choke and put my finger over the carb and cranked it through a few times. It drew the fuel up the pickup tube nicely. It started after a few more flips and idles just fine. I don't know if I'll bother with the prime bulb or not.

I wish I had known about this engine before I converted my 25cc Homelite leafblower engines. There was more cutting involved and I ended up buying the bigger carbs at $40 a pop. The 33cc already comes with the bigger carb so it's even cheaper to convert plus the power bonus.

So far it seems like it's going to be a great engine. How much does your GeeBee weigh and what prop are you using? What size is the GeeBee?

Jim