Thinking way ahead to the future Plans & Stick Build Along I, I'm planning to go big with a gas engine (not a huge surprise). If we're going to do an old-school stick-build, I figure an old-school engine would be most fitting. Three years ago I attended a swap meet and picked up an old gas engine. The seller didn't know anything about it, but it had compression and a $20 price tag. I was very new to gas at that time, so I didn't know what size it was, the brand, how to go about getting it running, etc., but for $20 I rolled the dice.
A few weeks ago I had to re-build the carb in an engine being used on a different project, and had an extra carb kit (they're cheap, so I keep a couple on-hand). I took the engine off the shelf, and it appears to be a Ryobi 31cc from a weed-eater, converted for RC use. The engine had a primer bulb, but to keep it simple I removed the brittle old parts and capped the line at the carb. Time to see if my $20 was well spent - well, $30 by the time I figure in the carb rebuild kit, gas line, etc.
I mounted the engine on my test stand and found it was pulling gas well enough without the primer bulb, as it still has the original slide plate choke. I had a 50:50 chance on the kill switch being in the right position (the switch isn't marked), so I hit the engine with the electric starter and..... nothing. Not even a pop. I flipped the kill switch to the other position and hit it with the starter and.... IT RUNS! In fact it ran pretty well at as I ran it near idle for a while to warm up for the first time in years. After sufficient time to warm up, Mike did his thing on the needles and got it running great! It seems just a tick slower to rev up to around 7,000 RPM than other RC engines, but from what I read that's normal.
The engine runs well and is much quieter than other engines, and should make a great power plant for an old-school type build.
This video is after it warmed up a bit, and before we started tuning.