Tach....

[Calibogue]

So I bought a TUFF tach that you wrap around the spark-plug wire.
The RPM is all over the place depending on how its wrapped etc etc.
Is there not a simple tach that just plugs into a harness?
This is a pain in the ass just to get RMP's for propping purposes.
FYI, this is a Yamaha 40hp tiller 2022 yr model.

[Palmetto Duck]

G luck I went through the same shit with Tiny Tach. Never could get it to read right. Call Power Tech tell them what you’re running and they’ll get you he right prop for your engine and what you want to do. I doubt you’re trying to squeeze every ounce of speed out of your 40 running up and down the river. You’ll be close enough on rpms it won’t matter.

[SouthernWake]

You can buy an old Yamaha tach to plug in or Go through the NMEA port if you have electronics.

You will want to monitor RPMs beyond just propping

[CUduckreeper]

When I had this problem a friend suggested just wrapping the tach wire around once or just enough so it would stay. That fixed my problem and it worked fine after.

[Calibogue]

I wrapped it every way possible.
Problem will be solved soon enough.....installing a Yamaha multi-function gauge permanently.