12V Lawn Mower Starter Solenoid for B-adBoy Zero Turn Mowers ZT, CZT, MZ 108-5349-00 MTD 925-1426A 925-1426 725-0771 725-1426 725-0530 925-0771 3 Post

What It Is

This 12V starter solenoid is the electrical relay that connects the battery to the starter motor when you turn the key. It’s designed for Bad Boy zero turn mowers (ZT, CZT, MZ series) and replaces several OEM part numbers across MTD and similar platforms.

Fitment & Compatibility

Before buying, confirm three things:

1. Pole configuration – This is a 3-post solenoid (two small trigger terminals, one large battery/starter post). Verify your original has the same layout.
2. OEM cross-reference – It replaces Bad Boy 108-5349-00, MTD 925-1426A, 925-1426, 725-0771, 725-1426, 725-0530, and 925-0771. If your mower uses a different number, measure your solenoid’s mounting hole spacing (typically 2.5”–3” center-to-center) and terminal sizes.
3. Voltage – This is strictly 12V. Do not use on 6V systems or high-amp diesel setups.

Check your mower’s deck size or model number against Bad Boy’s compatibility list (ZT, CZT, MZ with 48”, 54”, 60” decks typically use this style).

Key Things to Know

• Quality note – At $10, this is a budget aftermarket part. It works for most residential/light commercial use, but may not have the same corrosion resistance as OEM. Keep terminals clean and use dielectric grease.
• Installation difficulty – Easy. Disconnect battery negative first, unplug two small wires (mark which goes to which terminal), remove the large cable, and swap. 15-minute job.
• Common gotcha – If the mower clicks but won’t crank after replacement, the solenoid may be weak or your battery is low. Test battery voltage first. Also, some aftermarket solenoids have slightly different terminal thread sizes; check that your ring terminals fit snugly.
• Mounting – Uses two 1/4” bolts. Verify hole alignment; some aftermarket units have a slightly taller housing that may need a spacer or bending of the bracket.

Should You Buy It

Yes, if you need a quick, cheap fix for a Bad Boy ZT, CZT, or MZ with a dead solenoid and you’re comfortable with basic electrical work. It’s a solid value for the price, but if your mower gets heavy use or lives outdoors in wet conditions, consider spending more on a sealed OEM solenoid for longer life.