Tiny tach miss reading

[richp 0]

I installed a tiny tach on my 4040 with Onan twin. It worked on another tractor I had but now it reads real high. At idle it reads 3200 rpm's and at top speed, over 4000. I know it is running way under these numbers by sound. I have the wire that is spiraled around the plug wire on just one wire. I think I have a good ground to the block. Anyone else have a problem like this?

[Ronald Hribar 84]

I think and D17 can correct meif I'm wrong. But doesn't the onan fire on both cylinders at the same time, whether it is compression stroke or not. Probably not worded right either

[RayS 79]

which tach do you have? Does the 2 cylinder Onan fire 1X per revolution? http://www.tinytach.com/tinytach/gasoline.php