Farmpro 2420 Tachometer not working

nofd410 · Sep 4, 2017

Guys, I bought this little tractor 3rd hand and it does what i need for the most part but the tach has never worked, I had to replaced the tach with a new one anyway because the original came apart , anyway it still does not work, so thanks to this site i understand the RPM sensor could be the issue, so I pulled the sensor and this is what i found, the coil wire was hanging out and the magnet is worn as if it was rubbing against the flywheel, here's a pic, i'm thinking this may be my problem, your opinions are appreciated.

mrmikey · Sep 4, 2017

I'm thinking it was either set too tight from day one or it came loose and worked it's way in. I'd say time for a new one unless you can rewrap the coil

...........Mike

nofd410 · Sep 4, 2017

Yeah, it's a mess, I ordered one this morn from Circle G, $27.00, hope that does the trick, the magnet looks like it was grinding .

quicksandfarmer · Sep 4, 2017

It should be about 3/4 of a turn out from grinding. WIth the motor off, turn it in until it touches, then back it out 3/4 turn and tighten the locking ring. It's pretty common for these to fail, but it's an easy fix.

nofd410 · Sep 4, 2017

Thanks for that info quicksand, It'll be nice to have my tach working .

nofd410 · Sep 8, 2017

quicksandfarmer said:
It should be about 3/4 of a turn out from grinding. WIth the motor off, turn it in until it touches, then back it out 3/4 turn and tighten the locking ring. It's pretty common for these to fail, but it's an easy fix.

Quicksand, I received the new sensor, the wire colors are green and brown, I need to splice my old connector to the new wire which are yellow and white, does it matter which color connects ?

quicksandfarmer · Sep 8, 2017

I'm not positive but I don't think it matters. My understanding is the sensor is a tiny alternator, the steel teeth of the flywheel moving through the magnetic coil of the pickup generate a small AC current. Polarity doesn't matter with AC.

nofd410 · Sep 8, 2017

Thanks , the parts guy at Circle G said something similar , he felt like it really didn't matter but he also added " there's only one way to find out " , lol......