Tiny Tach won't work

[secretary of the marsh]

I've got an 05 M40D2 and have a Tiny Tach made for three cylinder engines on it. I ordered the tach direct from the manufacturer. No matter which plug, or how many wraps of the antenna I use, I csn't get a normal reading on the tach. It reads 800rpm or so at idle, but when running wide open, it only reads 3700 rpm. These numbers occur with the antenna on the middle cylinder only. Top or bottom cylinder are different readings. The bottom cylinder will read 7600 at wot, and idle at 1200 or so. The motors on a 16 foot jon. Any ideas?

 

[Mas]

Re: Tiny Tach won't work

Sounds like the tach is picking up interference from the other cylinder wires. Any chance to better insulate or reroute the other wires?

MAS

 

[deejaycee_2000]

Re: Tiny Tach won't work

It is picking up interference from the other cyl, it works best on the bottom cyl, wrapped 2 times around the plug wire .......

 

[pvanv]

Re: Tiny Tach won't work

Yes. Interference. If you call Tiny-Tach, they can probably advise you as well. Of course, there is the more-expensive Factory tach. I have one, and it works very well indeed.