I see your from Minnesota, I'm from Richfield. I got one of those MDS 78's too. 60 Bucks is a good price. Here's the poop, No nitro, yup, no nitro. This engine wants plain old FAI fuel, period. I got some morgan 0% and added a little extra caster for break in. Put it on a stand and run 3/4 gallon though it. It has a steel cylinder with a iron ring. It will take time to get the ring to seat. The steel cylinder really holds the heat , so no nitro. I used a wood 12x8 and turn the needle out 5 turns to break in. At 5 turns it blubbers and goes through 8 oz. of fuel in no time. Then do that thing where you pinch the line and lean it out for a bit and then let go and return to a RICH condition. I could hold my hand on the engine during this process, yes that rich. After that the engine had a good pop to it.

After that I put mine on WM p-51 with a 12-8 APC and a nice spinner, the model goes 12 feet than it goes up, up , up. Gotta leave it a bit rich for a while. My low end mixture was too far out. I ended up screwing it in all the way till the barrel wanted to jam at a closed condition and then backing off a bit. I also took the baffle out of the muffler, big help in transition and top end.

Remember, No nitro... have fun.

I also ground .040" off the opening side of the crank to increase port timing and "raised" the exhaust port .005 to do the same. The engine gained a good 600-800 rpm. Since the engine so cheap and the cylinder is steel it's easy to do.