JERRY - Have you had a Tiny Tach? And how long?
I had an early one, around 1990, it stopped working after an hour or two, I wanted it mostly for the hour meter function.
Bought a second one about 5 years ago, after our original forum moderator Bryan McMeen had worked with the owner of Tiny Tach to improve the tach's ability to withstand EMI, Electro-Magnetic Interference. SON mounted it on a freshly refurbished Cub Cadet 70 with completely rebuilt K241 engine, I never actually saw this one work, it failed after an hour or two. I think the Tiny Tach is a great idea, just needs much better implementation. My new 2016 Cub Cadet Tank zero turn had a tach/hour meter. The tach function stopped working after about 3 hours, was about done with the first mowing. The recording hour meter is still working fine at 256 hours.
If you want a good hour meter, a Stewart-Warner or HOBBS hour meter with the five revolving numbered wheels is about as reliable as they come. They just need hooked up to an ignition wire that's hot anytime the engine and ignition is powered, and OFF when the engine & ignition is turned off. My 72 has one of these with 1500 or 1600 hours on it. Just don't leave the ignition on.
Anybody got a better idea on a tach I'd love to hear about it. Stewart-Warner made the tach-hour meters used on IH tractors, not sure about the trucks, but the tractor tach/hour meters ran well over 10,000 hours.