Brian, there are several ways you can set the speed. You could use an ordinary electronic engine tachometer on the spark plug lead, but it isn't accurate enough to be especially useful - you need a digital tachometer. I set up a Lister driving an 8.5 kVA generator a few years ago. I began with an ordinary radio frequency digital counter, setting the gate time to ten seconds (as long as it would go) but that gave me a rather variable count. I switched to using a digital stroboscope on the camshaft (crankshaft isn't visible on a Lister - you crank the camshaft) and set the speed to exactly 750 rpm (it was a 4 pole alternator, so the crankshaft had to run at 1500). The Lister had a special optional governor - its whole adjustment range was only about plus or minus 1.5 Hertz. You won't be so lucky, but you should be able to get it to run at 3000 rpm at say 50% load.
