It certainly is not a stupid question. Briggs and Stratton has an inexpensive vibra tach that is reasonably accurate. Hold it against the engine and rotate the dial until the wire reaches it's widest sweep. It is difficult to work with on hand held equipment though, you need four hands. The digital impulse tachs are great but not cheap.

I agree with canguy, I have and use a Vibra-tech also. They are a simple tach that operate off of engine vibration and I believe that they are plenty accurate for small engine work. Tecumseh sells the same unit for less than Briggs does, both are the same unit that is made in Germany. They are quick and easy to use, I got mine from www.RCPW.com the part Number is Tecumseh 670156 and cost me $11.62 back in 8/05. If you want to call them their name is: Sohars All Season Mower Serv. Macedonia, Ohio Phone # 330-467-1332 Good luck!

Vibra tach. Treysit sirometer.

Link below.

Here is a link that might be useful: wunderbar

Try this http://www.shipstoday.net/products/Small-Engine-Tachometer-Hours-Meter.html I got one for a little boat and it seems to work pretty accurately.

Here is a link that might be useful: Small engine tachometer

Thanks for the find!

Here is a link that might be useful: Small Engine Tachometer