Starter Solenoid - Disappearing Power

[SHB]

Four terminal solenoid, so you should have 2 heavy wires (one from battery, one going to starter) and two smaller wires, one should go to ground (does it). The other wire is part of a series circuit that runs from the battery, ignition switch, seat switch and PTO switch and possibly a switch on the brake. These switches keep you from starting out of the seat, with the PTO engaged and with the brake off, any one of them not working or a wiring fault will keep the solenoid from engaging. If you run a wire from battery positive to the non-grounded side of the solenoid coil, does the solenoid try to engage?

BTW - I had an intermittent start problem on my Bad Boy mower, turned out the bolt on the positive battery terminal had loosened up, made good enough connection to run the mower, but didn’t always pass enough current to crank the starter.

 

[dana3132]

Please post the voltage results to each of the steps in my troubleshooting procedure. Then we can have a better idea on how you should proceed.

Hey Rivets, thanks for offering to help. Here's how far I've gotten, following your 6 recommended steps I've seen in other posts:

1. Confirmed fuse is good and clean. Scrubbed and cleaned the connections at the battery (looked pretty good, but disconnected and scrubbed anyway). Voltage at battery, while disconnected, is 12.71
2. Voltage at one of the large terminals on the starter solenoid reads 12.71
3. Voltage at the small white wire on the starter solenoid reads 12.6 when I turned the key. The other small wire never read anything on the multimeter but I think that's expected. I tried tracing that wire down to the chassis to ensure a good ground but due to where the wire is routed behind the gas tank and the wire shroud, I couldn't follow it all the way. I also measured the voltage at the fuse (with the fuse removed) and it read as 12.69
4. No power read at all on the other large terminal of the starter solenoid when the key was turned. I ensured the fuse was seated and that the small white and black wires were put back on tight on the solenoid and that the solenoid had a good clean connection to the chassis.

I also had the multimeter hooked to the battery while trying to start the mower and didn't see much of a drop at all. I have not had a chance to have a parts store test the battery yet.

The solenoid is fairly new (about 6 months old with less than 10 starts) but I'm suspecting it's the culprit. Looking forward to hearing your thoughts. Thanks again.

 

[Tbone0106]

If you went after it with a power washer or high pressure garden hose, it's likely that everything that can get wet got wet -- including everything under the flywheel. That's where the alternator is. First thing I'd do is pull the flywheel. It wouldn't surprise me if the problem presented itself pretty quickly after that.

 

[glensto68]

just a guess, but having mice making a home in it for a while, it sounds like they may have partially chewed threw a wire somewhere in the harness. most of runs under the hood up closer to the dash. That is where I would start.

 

[glensto68]

the small wire that you are getting power to when you turn the switch on runs through your safety switches, typically you have a brake switch, seat switch, and a pto switch if it is a lever system. If it has a clutch that operates the pto then the switch could be bad. to check it remove it look at it one side will have comm three times on one side. the number of terminals may vary. check for continuity from common to the out side terminals with the switch in the off position (should read 0) the pull the switch out and check from common to the inside terminals. should also read 0. make sure to check the terminals across from the common not at an angle.

 

[Rivets]

No voltage on the large terminal going to the starter when you turn the key, and no clicking of the solenoid means you have a problem with power going through the coil circuit of the solenoid. Disconnect the small wire going from the solenoid to ground and measure the resistance through this wire to a good ground. It should read 0 or very low. If it doesn’t you have a bad ground wire, which is simple to replace. You can also just take a light jump lead and connect it between the ground terminal on the solenoid to a good ground. Tell us if anything changes. Tbone, charging system has nothing to do with the starting system.

 

[dana3132]

If you went after it with a power washer or high pressure garden hose, it's likely that everything that can get wet got wet -- including everything under the flywheel. That's where the alternator is. First thing I'd do is pull the flywheel. It wouldn't surprise me if the problem presented itself pretty quickly after that.

Just used a regular garden hose and kept the spray mostly "down" but definitely got more water in places than a normal wash would.

 

[rminnehan]

Measure the battery voltage from positive to negative on the battery and then from positive to chassis ground. I have seen the negative wire not making good contact at the ground connection. If you have 12 volts or so between the terminals on the battery but not when you measure between positive on the battery and chassis ground you have a bad connection on the ground attachment, usually caused by rust and corrosion. Remove and clean then treat so it won't happen again. If the voltage readings are all okay you probably have a problem with the PTO or mower engagement switch (depending on whether you have an electric clutch or lever for deck engagement) or the break interlock switch. On the solenoid the black wire(s) are ground so should not read any voltage. The other one, sometimes purple, carries 12 volts and goes through the interlock switches. Sometimes the switches become physically loose in their bracket or there could be a bad connection at the plug.

 

[dana3132]

No voltage on the large terminal going to the starter when you turn the key, and no clicking of the solenoid means you have a problem with power going through the coil circuit of the solenoid. Disconnect the small wire going from the solenoid to ground and measure the resistance through this wire to a good ground. It should read 0 or very low. If it doesn’t you have a bad ground wire, which is simple to replace. You can also just take a light jump lead and connect it between the ground terminal on the solenoid to a good ground. Tell us if anything changes. Tbone, charging system has nothing to do with the starting system.

Disconnected the small wire from solenoid to ground and got 0 resistance.

I did change out the starter solenoid just as a precaution (scrubbed everything down to ensure good ground too) but still not starting. It is making a louder clicking noise now when I turn the key and it will last for about 2 or 3 seconds before stopping. Same other behavior has been noticed in that it will not repeat this behavior. I can turn the key once and get the hour gauge to turn on and when I turn the key I get the clicking but not twice in a row. Disconnect the battery and let it sit for a while and the cycle repeats.

 

[Rivets]

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.