Measuring RPM on a mower

[johnny7]

I was thinking of getting a digital tachometer because there have been a few machines in the past that I've worked on that 'appear to me' that they maybe running a little too fast.
Also, if I were to purchase one, they are very cheap $25.00CA from Amazon. My concern is that I will purchase one but not be able to use it because of the cowling on the mower. But saying that, I've never worked with one so I have no idea how it works.
I'd like to hear what others are doing for this.

 

[sgkent]

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..

 

[bertsmobile1]

I have 2 electronic tach
A Tiny Tach that has an internal inductive pick up so you do not have to connect it to anything , just point to the spark plug
And a much older inductive one with an antennea that needs to be almost touching the HT lead

 

[Hammermechanicman]

I like the DTI 20K.



And then if you slap a B&S number on it.

 

[bertsmobile1]

Gees you lot like to spend money
I thought buying the Fast-Tach, Wireless Handheld Tachometer $103.00 ( 4th one on the list ) at $ 100 was being extravagent
tiny tach
I like it because it is wireless and fits easy in my pocket
Sensitive enough to leave it on the bench while I adjust trimmers, blowers & chainsaws most times .

 

[slomo]

Speaking of tachs, anyone know how to change the battery in these exotic tachs? Mine has been dull on the contrast since I bought it years ago.

 

[johnny7]

thanks for all the advise. So, will something like this work for me then? And if it will, is it a case that I aim it at the spark plug?

 

[slomo]

thanks for all the advise. So, will something like this work for me then? And if it will, is it a case that I aim it at the spark plug?

View attachment 65832

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.

 

[Rivets]

I use a VibraTach like this. No battery or connections needed, just a little longer longer learning curve. Have one on the work bench and another always in the truck. https://www.jackssmallengines.com/j...mi75o1mbgogamvl_sucr3n6gwveaqyasabegl0uvd_bwe

 

[sgkent]

or $42 amazon or get a free app for your phone that uses you mic to pick up the RPM and is accurate.