Measuring RPM on a mower

[Rivets]

Johnny, photo units only work if you can see the output shaft. Definitely won’t work on lawn mower engines.

 

[johnny7]

Get the cheap one like I did at 11 bucks to your door. You don't need NASA tools for mowers. I wouldn't get that kind anyway. Mine simply wraps around the plug wire.

Thanks for all the recommendations.

 

[blaster 2023]

What

You have many choices. You can use one of the round spring wire things that sits on the mower where the spring oscillates at the harmonic of the RPM, or download an app on your smart phone. I have an optical one too that HF sold. You need a spot of white paint or something that spins so it can read it each time it passes. I use the spring wire thing on my mowers etc., but a sound driven one downloaded on you smart phone will pick up the RPM from the exhaust etc..

smart phone app?