1. I don't know why you want the engine upright, but anyway : you will have to redrill the mount holes and put in new blind nuts .

2. Sounds like it just needs a bit more adjustment ( high speed leave the low speed alone !!!! ) probably needs to be leaned a little.

3. You can try tightening the head screws/ bolts, you might also check that the glow plug has a gasket and is tight. As far as the fuel comming out of the muffler when tipped up, that normally would just be that you over primed or it's way too rich. It's not unusual to get a little fuel out of the muffler when tipped up.

4. I'm not sure of the RPM but when you find it and get it set BACK IT OFF ( richen ) about 2 or 300 RPM. It will keep the engine cooler and put less ware on all the neat parts, making it last longer.

Hope this helps . ENJOY !!! RED