Starter Solenoid - Disappearing Power

[VRR.DYNDNS>BIZ]

I am not sure if you replaced the battery but if you did not, yes you can appear to charge a battery that's bad and it will show proper voltage until you put a load on it and it drops to a very low value. A simple test of this is to put your meter (not the test light) right on the battery terminals. Turn the ignition switch on and off. Then repeat. Does the battery voltage stay over 12 for the entire sequence, or do you see a dramatic reduction when you hit the ignition the first time? If so then it's new battery time.

As a side note, I run into this all the time when servicing battery backup sump pumps(particularly the 'dumb' ones that don't cycle the backup DC pump and hence the battery). A battery that would normally last 4-5 years in a car or boat can go bad in a year or so. You pull the charger off and measure the voltage and sure enough it's 12+ volts, but put a load on it and it drops to a low value >>> battery is shot. That's because the battery is just sitting there 24/7/365 and never gets cycled. Shortens battery life dramatically.

Good luck!

A better way to make this test is to monitor the voltage at the B+ terminal and then the Motor terminal on the starter both in key off and key on. If at least 9 volts is present on key on, the starter is drawing current and should do it's job. If no voltage hits the motor terminal of 9volts or more but is present at B+ at the solenoid and the small control wire then the solenoid is not making motor terminals live. If 12 or battery no load voltage at solenoid b+ with key on but nothing on control wire then interlocks and wiring and ignition switch is your next troubleshooting loop. If mice have damaged and corrosion has set in then a way to simply bypass all interlocks and also make all safety features defeated but prove root cause is to find the start terminal wire on switch wiring and feed it directly to the control small terminal on the solenoid. This bypasses safety and will crank if battery and switch and starter and related connections are good. In your very first post you mentioned that on second attempt to start nothing would happen until waiting. This suggested 1) a auto reset circuit breaker or 2) corrosion, or 3) battery capacity. Battery capacity with a new battery should be no longer an issue if the new battery is good - which in my shop has found 2 bad batteries right of the gate, so to know this is not an issue, under an attempted load the battery voltage will always drop some, how much is important. This is where the highest load is the starter and a normal design is the battery should sustain such load and droop to no lower than 9volts. All other loads should be far less and hardly impact voltage any lower than say 10.5 or 11 volts. Good luck.

 

[dana3132]

Just to eliminate a possible cause, disconnect the ground cable froze the framer or engine, where ever it is connected. If you can measure the resistance through this cable, must be less than 5 Ohms. Clean the terminal and the frame down to bare metal, no paint and reconnect. We want to make sure that this connection is not a problem. Second, if you have materials ( 2 wire terminals and a short piece of braided wire) make yourself a jump lead to temporarily ground the solenoid. You can connect this lead to any good ground. When you install and test this it will tell us if current is going through thr primary circuit of the solenoid, you should hear a loud clipping sound.

OK - we're back in business. Still left scratching my head a bit but here's what happened.

First, I tested resistance through the battery's ground cable to the chassis and got 0 resistance. I took the cable off entirely and tested it by itself - again, 0 resistance. It is bolted down just above the rear tire and the bolt and ring looked pristine. Regardless, I sprayed it down with some WD-40 and hit it with a wire brush (the ring, the bolt, and the connection point).

Second, I made a jump lead to ground the solenoid. Undid the existing small ground wire (which was always reading 0 resistance, so I felt like I already had a good ground) and put my jump cable on and then connected to a bolt on the engine to ground it.

I hopped on the mower and it started up. Ran it for a while, turned it off, started up again. I undid my jump lead from the solenoid ground and hooked the original wire up - and it started. So it's got to have been a bad ground connection from the battery down to the frame. It looked really good to me with no corrosion but who knows. Should have tested after each step to know for sure but at the end of the day, I'm back up and running - finally.

Thank you Rivets for taking the time to read all these messages and guide me to a solution.

 

[Rivets]

Not a problem, I got lucky this time. Glad to hear you have it running.