14 Causes of a Failed Bobcat Zero Turn

When the air filter, spark plug, ignition coil, fuel line, fuel filter, fuel pump, carburetor, old fuel, or spark plug all fail, the Bobcat zero-turn mower will start but quickly die.

If the engine oil is too low or too high, if the cooling system is clogged, or if the mower deck is clogged, it may cease working.

If you read on, I’ll tell you about some of the factors that are adding to your running difficulties. To avoid injury, disconnect the spark plug wires before doing any repairs.

Bobcat Zero Turn

Before diagnosing, repairing, or operating, be sure you’ve read and understood all of the safety recommendations in the equipment’s operator’s manual.If you are unsure of how to proceed, lack the necessary expertise, or are unable to execute the repair properly, you should seek the advice of a professional.

Bobcat Zero Turn Starts Then Stops (Continues to Shut Down)

1. Poor Quality Fuel

If your mower’s fuel has been sitting for a while, its effectiveness may decrease. Ethanol, a byproduct of corn, is now a common additive to gasoline.

This item is corrosive to the fuel system and absorbs moisture from the air. Evaporation of this solution leaves behind varnish, which might limit fuel flow.

Your zero-turn won’t run if it can’t get the fuel it needs because of clogged fuel components. This solution will eventually separate from the gasoline and settle to the bottom of the fuel tank, clogging the fuel system in the process.

How to choose and keep your Bobcat mower’s gas in optimal condition:

  • Get new gas and use it up within 30 days.
  • Fuel with unleaded petrol that has an octane rating of 87 or above and 10% ethanol content, at the very least.
  • Avoid E15 and E85 gasoline, which contain 15 and 85 percent ethanol, respectively.
  • Keep gasoline in a cool, dry place, far from anything that could catch fire.
  • New gas can be stabilized by combining it with a fuel additive.

SOLUTION: Empty the old gas into a fuel container that has been approved. For this purpose, a fuel siphon pump is ideal.

Blend in some Sea Foam Motor Treatment to your fresh gas tank. Doing so will aid in de-watering and cleaning the fuel system. The fuel’s stability is also increased.

Put the gasoline blend into the gas tank. Turn the key and let the engine run to circulate the treated fuel.

2. Fuel Filter Clogged

To prevent debris from damaging fuel system components and the engine, a fuel filter is installed. To keep the fuel flowing freely, this filter needs to be changed out on a regular basis.

If dirt gets into the gasoline filter, the engine won’t have enough to run.

SOLUTION: A clogged gasoline filter should be replaced with a fresh one. Find the direction the arrow is pointing on the air filter’s housing by turning it around.

If your filter has one, make sure the arrow points in the direction of gasoline flow during installation.

3. A Fuel Supply Blockage

An obstruction in the gasoline line might be caused by old fuel’s sticky residue making its way through the fuel system. If this happens to your Bobcat mower while it’s running, the engine may eventually die from lack of fuel.

Use the fuel shut-off valve to start and stop fuel flow while examining each segment of the fuel line for fuel flow to locate any blockages in the fuel lines.

SOLUTION: If you discover a clogged fuel line, cut off the fuel supply and disconnect the fuel line from the mower.

Clean the fuel line and carburetor using carb spray. In order to unclog, do this. The next step is to use compressed air to blow through the line and dislodge the obstruction.

If you can’t get the blockage out of the fuel line, you’ll need to replace it and start the mower up with fresh fuel.

4. Broken Gasoline Pump

Vacuum pumps are commonly utilized as fuel pumps on zero-turn mowers. They force fuel through the carburetor by applying pressure from the engine block. The degradation of old gas can also cause mechanical failure in pumps.

Verify fuel flow from the fuel line to the fuel pump to discover if the fuel pump is malfunctioning. It’s possible you already did this in the previous step.

The fuel pump’s output should then be tested. You need to disconnect the gasoline line from the carburetor and turn off the fuel supply. Turn on the gasoline flow and start your Bobcat zero-turn after placing the line in the container.

SOLUTION: If fuel is dripping or pulsing out of the line, it means the pump is operating. If the fuel flow is insufficient, a new fuel pump should be installed.

5. Polluted Carburetor

Carburetors are used to control the ratio of fuel to air that is introduced into the engine’s combustion chamber.

Clogged carburetor components prevent the proper flow of fuel to the engine, resulting in slow performance or complete engine failure.

If you suspect your carburetor is at fault, here are some quick tests to run before you take it apart to clean it:

  • Verify that fuel is reaching the carburetor. If you’ve been monitoring the fuel coming out of your fuel pump, you should have already confirmed this.
  • Take the air filter out of its housing.
  • Start your mower after spraying carburetor cleaner into the air intake.
  • Carburetor trouble could be the culprit if the zero-turn starts, runs normally, and suddenly dies.

SOLUTION: Disconnect your zero-turn carburetor. Take it apart and give the carburetor a good scrub. For information on how to maintain your carburetor, read on.

If you would rather have someone else deal with maintaining your mower, bring it to a small engine repair shop or a Bobcat servicing dealer.

6. Filter Blocked with Dust

Your engine needs air to function properly. If your zero-turn mower suddenly stopped working, a clogged air filter could be the blame. When the filter gets clogged, it prevents air from reaching the engine.

Once a year, as well as multiple times during the mowing season, you should replace your air filter to maintain it clean.

Mowing in dusty circumstances will necessitate more regular cleanings.

SOLUTION: To maintain the efficiency of your paper air filter, follow these steps:

How to Change the Paper Air Filter on a Bobcat Mower

  • Take off the paper element of your air filter from its housing.
  • Use a clean, dry cloth to remove any lingering grime from the housing. Keep the air intake free of debris.
  • Tap it against a hard surface to loosen any debris stuck in the filter so that you can shake it out. Using pressurized air will ruin the paper.
  • Put your filter in front of the light. If the light is not passing through the paper element, the filter is damaged, or it is soiled with oil, you should get a new one. In such case, feel free to recycle it.
  • Put in a new air filter and replace the housing’s lid.

7. Clogged Radiator Hoses

When the cooling system isn’t kept clean, air can’t circulate correctly around the engine block and cylinder head, leading to overheating.


Scrub the air conditioner:

  • You should clean the cooling fins and replace any that are broken.
  • Clean off the engine shroud and the area surrounding the engine block.
  • You may improve airflow by installing your heat shield properly.

8. Low Oil Pressure in Engine

Before each use, make sure the zero-turn’s engine oil is at the proper level. Some people who use lawn mowers don’t do this. It doesn’t take long at all to quickly inspect the engine oil using the dipstick.

Recognizing a low engine level in your Bobcat mower before it causes engine damage helps prevent expensive repairs. Overheating and shutting down might occur with your zero-turn mower if the engine is not properly fueled.

Without adequate oil, the internal engine parts will grind against one another, generating heat in the crankcase. If your engine becomes too hot, the oil and other components could start to burn.

SOLUTION: If your mower shuts down due to an insufficient engine oil level, you can try to add more oil to rectify the level and restart your mower.

If your mower has turned off due to a lack of lubrication, adding more engine oil is probably not going to solve the problem.

There was probably a lot of damage to the engine. If you want to know how much damage was done to your mower, you should have a qualified small engine mechanic inspect it.

9. Over-Oiling the Engine

Having too much or too little engine oil might have the same effect on your zero-turn mower. Crankcase pressure will increase if too much oil is used. What happens when you use too much oil in your engine?

SOLUTION: If you discover that your engine oil level is excessively high after checking it, remove a small amount of oil.

A turkey baster or oil evacuator can be used to remove oil from the drain cap, the oil filter, or the oil fill area. The engine oil level must be rectified by repeated draining and refilling.

10. Dirty Spark Plugs or Loose Connections

If your spark plug is fouled, your zero-turn won’t start. If your Bobcat mower isn’t starting, it could be because the spark plug is dusty or the gap is off. If your mower is running slowly or dying, check the spark plug wires to see if they are loose.

SOLUTION: Replace the spark plug and, if necessary, clean it. A new spark plug should be put in if the old one is broken or has a particularly dark color.

Check that the spark plug wires are properly attached and that the spacing is set according to the engine manufacturer’s recommendations.

11. Ignition Coil Problems

When your mower becomes heated, the ignition coil’s winding can come loose and cause a short. The spark plugs won’t fire because they won’t obtain the voltage they need.

Because of this, your Bobcat mower may stop working after prolonged use.

SOLUTION: Use an ohm meter to look for a break in continuity to identify a damaged ignition coil. If you detect a crack in the ignition coil, you should get a new one.

12. The Position of the Choke Is Incorrect

The choke on your zero-turn increases fuel efficiency by reducing airflow to the engine’s combustion chamber. When the engine is cold, you can’t start it without this.

If you forget to turn off the choke once your zero-turn’s engine has warmed up, it will stop working.

SOLUTION: Check the placement of your choke lever. If the choke lever is in the correct position and a new, clean air filter is installed, but airflow issues persist, the problem may be a stuck choke plate.

Choke lever motion should cause plate opening and closing. If your choke is stuck, try cleaning it using carburetor cleaner.

13. Broken Gas Cap

The gas cap is made so that air can flow through it. If you block this vent, the fuel tank will develop a vacuum and no gas will be able to escape.

Even if your Bobcat zero-turn began off with a faulty gas cap, it will eventually turn off after being run for a long. This is because if air isn’t able to escape through the cap, a vacuum will create inside the tank.

14. Deck Plugged on Lawnmower

Overworking and eventually shutting down your engine is what happens when your mower deck gets clogged.

When grass accumulates under the mower deck, the engine has to work harder to turn the blades through the mess. The issue can be made much worse by dull mower blades.

SOLUTION: Maintain a routine of scraping the mower deck and sharpening the blades. A well-kept deck can reduce the load on your engine and make for a cleaner, more precise cut.

To raise and trim your lawn, the deck employs air movement created by the blades and the space under the deck.

Read more: Bobcat Zero Turn