Small Engines (Lawn Mowers, etc.)/L120 charging system
QUESTION: Hey Eric, I've got a John Deere L120 that isn't charging the new battery. I put in 106777-0128-e1 into the B&S website to see about downloading,purchasing or asking for help but it says it doesn't have any results for that nmbr. The nmbr came off of the engine,more specifically the ohv cover. Do you know if their website is only operational between 9-5 Mon-Fri? Or why they don't recognize the engine model nmbr? Better yet, do you know of a link to a step by step process of checking the charging system? Here's where I'm at presently. Btty shows 12.5 v, voltage regulator shows about 29 VAC at yellow wires and 12.5 VDC at red wire at full throttle. I have jumped it off with my truck 3 or 4 times before I got the new btty. And I've seen where that is a no-no. So I guess it's quite possible that I shot myself in the foot and fried the regulator. Should I take a 60-80 dollar guess and get a regulator or take the time and try to troubleshoot it? Ain't nothing ever simple,is it? Sorry about the length of the question. I 'magine you're a fast reader. And I do appreciate wisdom from perfect strangers. Many thanks.....Man!!,65,000 - character limit. I've got room to tell you about my grandkids.
ANSWER: Try these URLs:
Double check the model number. Based on the first 2 digits (10) it indicates it is a 10 cubic inch block which is a small, walk behind mower engine.
Let me if the URLs helps.
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QUESTION: Appears to be 406777-0128-e1. I'm trying to find a tach of some kind now to do the test on the URL you sent me. I guess it's best to check at 3600 rpms like they say? Do think jumping it off probably hurt the regulator or not always? Thanks for the speedy reply.
ANSWER: I wouldn't worry about a tach. You AC voltage readings should be in the ballpark...it the alternator is bad your AC will be way off.
I have ruined regulators, diodes, switches, wiring...with using a car battery...too many amps. There was usually other issues that contributed to the parts getting ruined.
The AC volts should increase with engine speed and decrease when the engine is slowed down.
The regulator should have DC output if the AC input is good.
Make sure you check the wiring, connections...make sure everything is clean and tight as well as no shorts in the system.
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QUESTION: Hey Eric, I had been checking DCV at the regulator with red wire plugs together and my test lead on the battery side of the connection. I disconnected the plug and checked red wire out of regulator and had 13.7. Had a bad connection at the plug. I appreciate your wisdom. I was leaning towards a new regulator. You did good. Many thanks. Enjoy your 30 minute weekend.
Make sure you keep you battery terminal clean...they might look clean, no corrosion, but is it a wise to disconnect the cables and clean the battery posts and cable ends with a wirebrush once in a while. This will ensure a good connection and keep the resistance down. Check out Ohm's law, increase resistance lead to more current...current, not voltage, leads to more heat which can cause components to overheat and fail...plus it ensures your starter is getting max current to spin the engine.
Glad to hear it was just a connection.