Bad Boy Mower Problems [Troubleshooting + Fixes]

Over the years, the Bad Boy brand has built a reputation for manufacturing some of the most heavy-duty lawnmowers for landscaping.

Most common bad boy mower problems include; transaxle and hydraulic issues, deck lift failure, deck shaking, spindle, and alignment issues. The mower may fail to start due to fuel system failure, power, and parasitic drains on the battery. Trouble shoot these problems at home or seek technician assistance.

Below, we look at some common Bad Boy mower problems, how to troubleshoot them, and the recommended fixes and repairs.

Comment below (at the end of the article) asking about your specific problem and we’ll try to help you find a fix.

Can you troubleshoot a Bad Boy Lawnmower at home?

Bad Boy Mower Problems

You can troubleshoot your mower at home if you have the technical skills and the required tools. However, I would recommend you call a certified mechanic to help with some problems such as a leaking hydraulic fluid, replacement of filters, blades, and even a whole transaxle.

For major problems, it is best to check your warranty and call it in so that a Bad Boy certified service technician can help you fix some of the problems at an expert level. It’s good to note some of these problems can be characterized by increased lawn mower noise or decibels.

7 Most Common Bad Boy Mower Problems

If you’ve used a BadBoy mower for a long time, you probably know that most common faults start with the mowing deck, starter, and transaxle. Most of these occur due to a lack of proper maintenance, wear, and tear, and sometimes the wrong usage.

Here are some of the most common mower issues and the best way to repair and fix them.

Electric deck lift problems

The electric deck lift of your bad boy mower can cause problems such as the actuator failing to lift or lower the deck. This could be due to shaft failure in screwing in and out, even if the actuator spins. To repair your actuator and solve your electric deck lift problems, you’ll want to unscrew open your actuator and check for the presence of moisture on the actuator housing. In case it’s damaged, you should get another actuator. You should also check to ensure that the housing is properly sealed.

If poor house sealing is the case, you can apply a sealant gasket to correct the problem. However, if the issue is the presence of rust on the screw shaft’s sleeve, clean it up, apply grease, and check again to see whether your deck now lifts and lowers properly.

Transaxle and hydraulic problems

Bad Boy mowers have a great suspension system that makes the ride smooth while keeping the mower deck stable even when mowing on uneven terrain. At the same time, you get an unmatched, smoother, and cleaner cut.

However, transaxle and hydraulic problems can rough your ride and produce bad cut quality on your grass. This can be bad for most sensitive turfgrasses that need a clean-cut quality and mowing height, e.g., Bermuda grass.

Common bad boy mower transaxle problems include:

  • Leaking hydraulic fluid
  • A damaged charge pump

The best fix for a leaking fluid is to get a new seal kit and install it. The hydro system may also be faulty so you might want to get a mechanic to inspect it and fix any faults there.

Mower pulling to one side; alignment problem

Another common problem you may encounter with your Bad Boy Mower is the alignment issue. The tractor pulls to one side as you mow your lawn and easily gets off the mowing track.

This is a steering problem whereby regardless of what direction you want the mower to go, it deviates off the mowing line and goes in the wrong direction.

While several different faults can cause the problem, the most common reasons you might want to check out include the following:

  • Some tires have better grip than others.
  • A faulty dampener (shock absorber) on one side.
  • Handling and steering problems (poor adjustment)

This has happened a lot on the Bad Boy ZT with a 50’’ deck where the mower is, but the good news is that you can easily diagnose your zero-turn mower and even be able to fix the alignment problem in many cases.

How to fix a mower that’s pulling to one side:

If the problem is not a serious mechanical or transaxle fault, there are a few fixes that you can try to get rid of this problem. Here’s how to fix the issue:

  1. Balance wheel pressure accordingly

Your Bad Boy tractor will drag to one side- if the wheels on one side are underinflated. The easy solution is to check tire pressure to ensure all wheels have the recommended PSI. This should fix the problem.

2. Fix hydraulic problems

Hydraulic issues can vary and produce different faults and their signs. To fix this, you might want to check if there’s any oil leak around the transaxle parts. If there is, a new seal kit may be needed, but the best solution is to call a qualified mechanic.

Mower deck shaking

Bad Boy mowers are usually sealed decks, but after hundreds of hours of mowing, the blades will need some servicing and even the deck checked.

One common problem is cutting deck vibration or shaking, which can point to missing set screws from pulleys and lock collars. If the spindle key is also worn out, the deck will start to vibrate or shake when you start and run your Bad Boy mower.

This fix is as simple as tightening the belt adjustment at the back of the drive pulley. You can also check and replace any missing screws on the pulleys, the spindle, and the bearings.

If this does not fix the problem of a shaking mowing deck on your Bad Boy zero-turn mower, check to ensure the blades are balanced – especially if you installed new blades under the deck. If you are a DIY kind of person like me, it’s good to know if lawn mower blades are reverse threaded to avoid such a mistake.

If this issue persists, you might want to have the tractor checked by a certified maintenance mechanic for further troubleshooting and repair.

The mower won’t start or move

A lawn mower that won’t start points to a fuel pump or fuel system fault, which is common in most gas-powered self-propelled lawnmowers. If not the pump, the fuel injection line is likely the cause of the problem and is worth checking.

Even a new pump can be dry and cause the mower not to start or move when mowing the lawn.

Replace the fuel pump, or troubleshoot the fuel line to ensure fuel is running in the engine.

Another important fix is to check the spark plugs to see if they are properly mounted. If the plug is loose, the mower won’t start or can stop moving while in the middle of mowing. Ensure you check the battery metal terminals connection, and don’t forget the mower operates on battery. Connect the battery well and check the charge available. It may be the problem.

No power problems

Sometimes, your Bad Boy mower just won’t start. It could be that you’re hearing the relay when you turn the start key, but the motor just won’t turn over. If your mower won’t start, you should troubleshoot for the following:

  1. Battery problems– such as low charge or improper battery connection. Measure the charge and check if the metal terminals are loose.
  2. Fuel tank problems– such as use of old fuel (over a month old) or the presence of water in the fuel tank.
  3. Spark plug problems– such as unattached spark plug wire.
  4. Dirty air filter– a clogged air filter makes raw air into the engine hard.
  5. Faulty wiring and loose connections.
  6. Failure to observe the proper mower starting procedures. Ensure you service your bad boy lawn mower with a genuine bad boy mower service kit and oil.

Spindle problems

Faulty spindles can result in uneven cuts on your turf as they’re a crucial component of the mower’s cutting deck. For owners of Bad Boy lawn mowers, some of the spindle issues that they’ve reported in the past include:

  • Squealing noises- if your mower is making squealing sounds, it’s highly likely that the spindle is damaged or they have worn-out bearings.
  • Low buzzing sounds- the bearings in your spindle may also cause low vibration noises if they’re worn out.
  • No immediate heat-up- if your spindle only heats up after about half-an-hour of use, you could be dealing with a spindle preload issue.
  • Visible damage- if your spindle is visibly bent or damaged, resulting in uneven blade spinning, you’ll need to replace it.

To fix the damaged spindle on your mower’s cutting deck, you’ll need to remove and repair the existing spindle and reinstall it. Alternatively, you can purchase an entirely new spindle and install it. Finally, if worn-out spindle bearings are the issue, you should consider replacing them too.

Read More: Lawnmower sputtering causes and fixes

What is the warranty on Bad Boy mowers?

The Bad Boy brand provides comprehensive warranty cover for all its commercial lawn mower products. This includes the free repair and replacement of defective mower parts for up to two years from the time of purchase. Defects can either be classified as material defects or workmanship defects.

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  1. I have an MZ Magnum 27hp
    When I kick on the mower blades to mow my lawn, RPM drops to anywhere from 1800-2000 RPMs; it will idle at 3400 RPMs. Please help.

    1. One thing that’s for sure is that most of the Bad Boy tractors we buy come with engines that are not adjusted for the specific mowers they’re mounted on. As such, RPMs can be high when the mowing deck/blades are not engaged but drop drastically as soon as you kick on the mower blades.
      I would start by checking the governor setting for this to see what’s set as the maximum RPMs.

      1. When I engage the arms, my MZ Magnum dies. Parking brake disengaged and seat sensor seems to be working fine.

      1. Hi Chris,
        My bad boy 725 won’t engage the blades, I’ve replaced pto switch but didn’t help. Any other ideas?
        Ron Cole

    1. Hydraulic deck will not work on my at elite 60 bad boy. Dealship said they don’t know if they can get the parts or when they can get the parts because they come from China. Can I get them from Batesville, Ar. Or somewhere else.


    1. Electric. When you turn the key to “on”, can you hear any relay/solenoid clicks. If no, the brake safety switch and two arm safety switches need to be checked. If yes, your starter solenoid could be faulty. Hopefully it was one of those. After that, the bank of relays that make up the interlock logic should be looked at. Their functionality is complicated, I would first check that the relays are not faulty. Shake test is easy, though far from precise; but I’d still give each a little shake for rattles. If one does, check it first. By checking the relay, I mean check for continuity between pins when energized (12V) to coil. If your relays are ok, connections, opens, and shorts should be searched for.

  3. Electric deck lift not working. When you push switch in nothing happens no sound or anything.

  4. Hello, my name is James Fenner. I own an MZ Magnum Bad Boy Mower. I serviced it last month and parked it until this month. After I serviced it, it started right up and ran like a top. I started to use it and it would not start. It would not even turn over. My first thought was the Battery. It was 5 years old. So I replaced it. Again it would not start. So I tried bypassing the start solenoid. It started right up and I did some mowing. So I ordered a start solenoid for it and installed it. Same thing will not start unless you bypass the solenoid. What else do you think might be wrong. Thank you James E. Fenner

    1. Check your drive handle position sensors, you can wiggle the wires going into it and see if it will start with the key turned.

    2. My electric deck does not lift or lower deck does not make a sound when trying to lift or lower deck always kept inside never got wet

      1. I have zt 60 inch 27 hp it lose power when blades engage. Disengaged motor runs at proper speed. Any ideas??

    3. You may not have a good ground for your solenoid. The signal voltage. Use thread forming screws to attach another solenoid.

  5. Bad Boy Mower runs flawless for about 45min then acts like its running out of fuel. Shut the pto off and it clears up. Start pto back up runs another 5 min fine. After that. Will not continue to run.
    Let it rest several hours and it will run fine again for about 30 min.


    1. Identical problem with mine. My dealer has no clue and I’ve had this problem for years. I have replaced PTO switches, fuses, batteries, and more. It’s like the PTO causes too much electrical load on the system. I need help too!

      1. I am having identical problem with my bad boy rebel. Did you figure out what to do to fix it?

    2. My 2013 ZT Elite has just started this behavior. Did you ever figure out the issue or resolved.

  6. ZT Elite runs when stationary. Blades can be engaged no problem. When you move the handles to start mowing, it shuts down.

    1. Have you figured it out? Mine want to shut off like the brake is on or seat goes up when I try to move

      1. I’m running into the same problem with mine, cranks up and runs great while sitting but just as soon as I try to move the drive bars it dies. I can run the pto no problem with brake engaged or disengaged. Any help would be great!

  7. My maverick keeps on breaking the hydro pump belt. Sometimes only 5 or 6 hours! It almost looks like an alignment issue…?

  8. Handles will not accelerate th mower even if it starts and the pto works

    I unfortunately mowed some tall wet grass

    Then heard a squealing sound

  9. I have a 2010 Model MZ4800

    There are two fans sitting on top of the left & right hydro gears. Both fan blades are hitting the metal frame, when the mower is running, shearing off all blades on one side & 1/4 of the blades on the other side. Bad Boy stated a new belt (which it needed) would bring those two pulleys (inward), away from the frame to prevent the blades from striking the metal frame. Nope. Those spindles the pulleys sit on, are stationary. Not going anywhere.

    I paid close to $100 for ONE fan, that came with a new pulley & a new belt. I’m not about to run that mower & shear off the new blades!

    Am I not adjusting the tensioner correctly? Ever heard of this issue? Still, the pulleys won’t pull in away from the outer metal frame.

    Only other fix is to get a torch & create a larger hole in the frame to prevent the blades from hitting it.

    Not even sure what the purpose of the fans are. I suppose to cool the hydro gears? Funny because they sit behind the seat on top of the hydro gears.

    HELP! Nothing on the WWW has any information on this.

      1. When you push handles forward to go, right goes fast but left side hardly moves. What could cause this problem???

  10. I work for a school district and we recently purchased 5 Rebels. We have been having problems with the dials not staying in selected height and the deck lock won’t stay locked when transporting. I like to float my deck around tree roots and other objects you run up on. With the dial spinning freely every time you lift the deck just a little to go over a object you have to go back and set your height every time. It makes it so annoying not being able to float your deck.

  11. Bad boy pro Z 60 inch 27 Kawasaki blowing fuse when PTO switch is pulled without it running unhooked pig tail (which diode was burnt) still pops 25 amp fuse when functioning PTO?

  12. I have a 2014 48″ cut, ZT Elite with a 7000 series Kohler engine. The mower runs fine until I engage the PTO then I hear a loud metallic grinding noise. I’ve checked the belt and pulleys and they seem fine. What else could the problem be?

  13. I have a ZT Elite 60″ with Kawasaki engine, it is about 7 years old and has been great until recently. I stopped to move some things out of the way and when I got back on the mower I engaged the PTO and the engine bogged down and shut off, the blades/spindles are free and belts are not binding, battery shows 12.02V. The mower cranks, runs and drives fine. Does it seem like my problem lie in the PTO switch or electric PTO Clutch?

  14. Bad boy it starts put clutch down and shuts off. Put a new switch by the clutch once before and it was fine just put another one on it and it still shuts off any idea what I might be

  15. i hace 60 in cut 27 kawaski it keeps burning up selnoids replace selnoid it will crank a few times then burn another , i have replaced the starter still have same problem

  16. 2017 bad boy mz magnum does nothing when ignition is turned. Can start across cylinoid. Replaced cylinoid, all fuses, relays and ignition switch. Battery is charged but still nothing. I’m stumped.

  17. Badboy zt kohler 700 wont start but will turn over. I have replace the carb and fuel pump. Also getting spark in spark plugs. also check all the relays and switches, all are working as they should….but i can make it run with starting fluid. Any advice as to why it might not be starting?

  18. The deck actuator only runs in one direction. I’ve replaced lift switch and took apart the actuator and cleaned it thoroughly but it will only turn in the up position…. Thanks

  19. Deck will not lower or raise,electric, and engine skipping only when blades engaged and loaded or pulling.

  20. Bad boy zt elite runs fine till I turn on the blades then it’s like the blades are half throttle barley will climb a hill or mow with blades on

  21. mower cranks mows perfect for about 10 minutes then starts putting and acting like its going to stall put new fuel filter on it still same problem.

  22. I have a bad boy rebel Kawasaki engine led meter for hours and rpm started smoking getting very hot !!!! Throttle will not work now I unhook battery parked it in garage!!!! 43. Hours on machine