by walt » Sat Feb 16, 2008 9:17 am
I used to run them when I was a kid, but only remember that they were not very powerful for their weight. I'd say, first make sure yours draws fuel, and will run out a prime. Low nitro and high castor content probably, tho I certainly didn't know/care about that back then. Probably a long thread plug as long as it doesn't hit the piston. Don't remember what was in mine. Check for air leaks and plugged NVA if it won't draw fuel, or won't keep running. If it will run out a prime, then there's probably a problem from the NVA back to the tank. They're not high revvers, so a long prop as Max said. I assume it has good compression and no leaks around the head gasket. Hold it upside down and rotate the prop and you should see bubbles if it leaks. Or immerse the head in gasoline/kerosine etc and rotate the prop to check for bubbles. Also, possible leaks around the case gasket. Look in the exhaust to see if the piston is in backwards. The baffle should be on the intake side, not the exhaust side. Looking at the head might give you a clue there, but can't remember about plug offset. Also, do they have rings? I forget. The rings might be stuck, but probably not if it has good compression. I'd start out checking the fuel draw, fire, etc. before you get into checking this other stuff.