Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I just got one of these Vibra Tachs.  I need it to measure rpm on my diesel power plant.  I have the instructions and read them but I'm still not clear on it's operation so these are a few questions to those who have used one. 

Do you hold the device on a flat part of the engine and slowly turn the inner ring until the wire comes out far enough to start to vibrate?  If you go further out does the wire stop vibrating?   How much of a vibration arc does the wire achieve?  Less than a quarter inch? eighth inch?  etc...   Any help will be appreciated. Thanks.

i have a briggs and stratton vibrating tach like i believe your talking about.you slowly advance the wire  out of the housing until it vibrates at its largest  gap. if you go to far it will narrow back down again.advance the wire slowly and  the widest vibration point is the rpms of what you are checking.i have used it to check deck speed,engine rpm's , governed  full rpm speeds, etc. go slowly and  it is suprisingly accurate. you can fool around with it on a vehicle with a tach and get used to how it reads. mkd

Thanks for the reply. 

 I took the Vibra Tach out yesterday and tested it on my snow thrower.  I have a small digital tach on the Simplicity and did comparison readings to get an understanding of how the device worked.  I found out that when the wire is vibrating in sync with engine, it will be at it's widest arc.  I took several readings at various rpms and I must say that it's uncannily accurate.  The simplicity of this device is amazing.  It is a pain to use though because of it's size and the requirement to use both hands to operate it.   The size issue is more of a problem with trying to find a flat surface big enough on small engines.  For my needs however (to measure rpm on a diesel engine) it will be perfect.   

Borat,

Glad you like it, works great for me also!

Told you it would work on your diesel  !

                              Fred

jubol wrote:

Hi Fred:

You're right bud.  Best piece of advice I've picked up in quite a while.  I'm still amazed with that little thing!

Thanks.

Just curious since I've never seen one [though I did just order the Tecumseh equivalent]-

Will I be able to tell how fast my impeller is turning with this thing?      

Jim

elbrecht wrote:

That's an interesting point Jim.  The instructions say that in some instances where there are more than one rotating part (i.e. gears)  it may not read accurately.  However, I'd be willing to bet that it might be able to read the impeller if you place it on the impeller housing ensuring that you keep it as far away as possible from the auger.  Be very careful working around the moving parts.   I'm going to give it a shot on my machine once it warms up a bit.  It's been minus 20C here for the last couple days and down to - 39C with the windchill.