And now---I have a strange story to tell (but it has a happy ending). Couple of days ago I had the engine setting on my side desk, chugging away happily, and I was congratulating myself on what a clever fellow I was to build an engine like that. And then----it quit!!!
Well Poop!!--Must be out of gas. Opened my fancy blue gas tank, and it had lots of fuel. Okay, if it isn't fuel. it has to be spark. I pulled the sparkplug out and laid it on the cylinder head and cranked the engine. Lots of spark!! Well sir--What do I do now? The automotive gasoline in the tank had been changed out for Coleman fuel, because Coleman fuel doesn't stink when it's being burned. Maybe the engine was seizing up, but I've never really had that happen. I grabbed the flywheel and gave it a couple of spins, and it turned freely, so determined that the engine hadn't seized. Maybe the set screws in my ignition cam had slipped and the engine had "jumped time". Checked those screws out and they were tight. Maybe the set screws in one of my timing gears had slipped and the valve timing had gone screwball. Checked those set screws and they were still tight. Maybe the Viton piston ring had failed and I had lost compression--but no, engine still has terrific compression when turned over by hand. Maybe something wrong with the carburetor--but no, those carbs don't have any small moving parts that can fail or vibrate out of place. How strange!! My engine won't run, and I can't diagnose what is wrong. Had some serious thoughts about making another head with a vertical sparkplug in it (A 1/4-32 sparkplug would fit beside the valve cages)--I laid it out on my 3D program and it would work, but Damn, there's a lot of work in making a cylinder head. I looked at my files from ten or eleven years ago when I built my own sparkplug for the Kerzel engine, but I really didn't want to do that. Went to bed, disgusted with small engines in general. Today I thought, "If the engine ran okay (which it did) and the engine then stopped without any clanks or bangs or obvious signs of distress (which it did), then what can possibly have changed? I pulled the sparkplug out and looked at it under my lighted magnifier, and seen that the spark gap was only about .005". Enough to give a bright spark when laying out on the cylinder head but not enough to light the charge of fuel under compression. Fetched out my trusty jacknife and opened the gap to about .025" and reinstalled the plug. Engine started right up and ran like a race horse. Relief, relief!!! I have no idea what closed the spark gap up while in the engine. Maybe a piece of dirt from when I was trying the piston with the cast iron rings. Maybe it was the bad engine fairy.--I don't know, but man, I'm glad I got it sorted out without having to remake anything.
