chev0545 231 #1 Posted May 23, 2017 have a 1975 c-120 not charging where to start has a new battery thans Share this post Link to post Share on other sites
rmaynard 14,911 #2 Posted May 23, 2017 (edited) First place to start is to check and see if ALL of your battery connections are clean and tight, including the connection to GROUND at both the battery and the frame. Put a multimeter on the battery with the engine running. If the charging system is working, you should have a reading of about 13.5 to 14.5 volts DC. Edited May 23, 2017 by rmaynard Error in text 4 Share this post Link to post Share on other sites
pfrederi 17,147 #3 Posted May 23, 2017 Download the engine manual. it covers the diagnostic test for the charging system in section 8. as Bob said check all your connections. (Also make sure the regulator body has a good ground to the tractor). if you donot get 13.5v to 14.5 volts running then go to the manual 2 Share this post Link to post Share on other sites
slammer302 2,154 #4 Posted May 23, 2017 rmaynard is right. If everything is clean and connected right i would start looking at the voltage regulator witch i believe is the metal box under the dash on a c-120 and checking the stator. witch is behind the flywheel and has two wires from it plug into the voltage regulator. someone correct me if i'm wrong just going off memory. Share this post Link to post Share on other sites
daveoman1966 3,612 #5 Posted May 24, 2017 The C-120 (and similar) has a regulator / rectifier that converts AC from the stator to DC to charge the battery. This rectifier MUST be grounded to the body/frame to work properly. Every one that I've ever seen is CORRODED at the 2 bolts that mount it, thus loosing the necessary ground. It is (usually) in the hoodstand, just under the steering wheel and has coolant fins on it.... Disconnect it and shine up the mounting base...clean all the crap from it. Brush up the 3 male spade terminalls too, then make sure the female slat spade wires make a tight fit....crimp them a little with needle nose. When reattaching the 3 wires, put some bulb gears or something else to stop the corrosion. 3 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,504 #6 Posted May 24, 2017 I think Dave's gears were turning and meant "bulb grease" which is like a dielectric silicone grease to stop oxidation. Garry 2 Share this post Link to post Share on other sites