Begin looking for a starting problem by checking the items that can prevent air, fuel, and spark. These are the three requirements for a combustion engine to start.
A Black Max mower won’t start due to a plugged air filter, wrong choke setting, bad spark plug, faulty ignition coil, plugged fuel filter, clogged fuel line, dirty carburetor, or old gas.
Keep reading for a full list of items that can cause your Black Max starting problem. Make sure you follow all safety guidelines in your owner’s manual before performing work on your mower.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
12 Reasons Your Black Max Mower Won’t Start
1. Empty Gas Tank
You know your mower requires gas to run. Don’t skip checking the fuel tank. You may have developed a fuel leak or the gas gauge may have stopped working causing you to run out of gas sooner than you thought.
SOLUTION: Check over the fuel system and look for a leak or faulty fuel gauge. Repair or replace faulty items. Fill the gas tank with fresh fuel.
2. Fuel Valve is in the Off Position
Check to make sure the fuel valve is not shut off and remains in the on position. You may have shut the valve off when working on the fuel system or before storing your mower.
The engine won’t get fuel when the valve is closed.
SOLUTION: Place the fuel shut-off valve in the open position.
3. Bad or Old Fuel
Gas sitting in your fuel tank for extended periods can become unstable and break down causing running issues and gumming in the fuel system.
Gummy deposits in the fuel system can clog components restricting the fuel required to run. This will prevent your engine from getting the fuel needed to start.
Because fuel can begin to break down as soon as 30 days after purchase, use your fuel within this time frame or add a fuel additive to stabilize your fuel so it lasts longer.
I use a product called Sea Foam Motor Treatment. It not only stabilizes fuel but also reduces moisture and cleans the fuel system.
SOLUTION: Drain old fuel from your Black Max mower. A fuel siphon pump work well. Mix gas with a fuel stabilizer and add the mixture to the fuel tank.
Use gas with a minimum 87 octane rating and maximum 10% ethanol content in a Black Max mower with a 4-cycle engine.
4. Bad Fuel Cap
A fuel cap is vented to allow air to pass through the cap. When the vent in the cap becomes clogged, your fuel tank will not be able to vent causing it to form a vacuum restricting fuel from flowing out of the tank.
SOLUTION: Run your mower with and without the fuel cap. If it starts without the cap but eventually shuts down after replacing the fuel cap, you may have a cap that cannot vent.
You can attempt to clean your cap to remove the cap or replace it with a new Black Max gas cap.
5. Incorrect Starting Procedure and Operation
Black Max push mowers use a blade control lever as a safety feature on the mower. This is a safety procedure that will prevent the mower from running when the operator is no longer present.
The blade control lever must be pulled back and held against the handlebar to start and run the mower.
SOLUTION: Make sure the blade lever is held against the handlebar while turning the ignition key on an electric start mower or pulling the recoil on a manual start mower.
When the blade control lever is released, the engine will stop and the blades will not continue to turn.
6. Plugged Fuel Filter
The fuel filter strains your fuel to prevent dirt from entering the fuel system and your engine causing damage.
The fuel filter can become so plugged that a sufficient amount of fuel isn’t able to pass through it and flow to the carburetor.
SOLUTION: When you find the filter is plugged, remove it and replace it. You will find many filters that will have an arrow on the side of the fuel filter.
The filter must be installed with the arrow pointed in the direction of your fuel flow.
7. Blocked Fuel Line
Dirt and deposits formed from running old fuel can cause a blockage in the fuel line.
SOLUTION: Check the fuel line by stopping your fuel flow using the fuel shut-off valve. If your Black Max mower doesn’t have a valve, clamp the fuel line to stop the flow.
- Remove the end of a section of the hose furthest from your fuel tank and place it in a container.
- Start your fuel flow and make sure you are getting fuel into the container.
- The container must be placed lower than the fuel tank. Fuel cannot run uphill.
- If you don’t get a good flow of fuel out of the fuel line into the container, stop the fuel flow and remove the fuel line from your mower.
- Spray carburetor cleaner in the line to loosen up the clog.
- Use compressed air to blow through the line to remove the blockage.
- If you cannot free the line of the clog, replace it with a new fuel line.
8. Bad Carburetor
The carburetor’s function is to regulate the amount of gas mixed with air to form combustion in the cylinder. When the carburetor is dirty and gums up from old fuel, components in the carburetor no longer function properly.
The carburetor may not allow the release of gas required to start your Black Max mower.
SOLUTION: If you have verified you are getting fuel to the carburetor, remove the air filter and spray carburetor cleaner into the air intake.
Start your mower. If it starts, runs, and then shuts down, disassemble the carburetor to clean it. You can find instructions for cleaning your carburetor here.
9. Clogged Air Filter
A plugged air filter can restrict airflow to the mower and not allow the engine to get the air it needs to form combustion. It is best practice to replace your air filter annually. Check and clean your air filter regularly.
Clean a Black Max PAPER air filter:
- Remove the air filter from the housing.
- Wipe out any dirt remaining in the air filter housing and cover. Don’t allow dirt to fall into the air intake.
- Inspect the paper air filter. Tap the filter to loosen dirt so it falls from the filter.
- Hold the air filter up to a light source. If you can see good light go ahead and reuse it. If you are not getting good light or it is very dirty, damaged, or no longer seals the air intake sufficiently, replace it with a new one.
- Install the air filter.
- Reattach the air filter cover.
Clean a Black Max FOAM primary air filter
- Remove the air filter from the housing.
- Wipe out any dirt remaining in the air filter housing and cover. Don’t allow dirt to fall into the air intake.
- Inspect the foam filter for damage and replace it if needed.
- If the filter is in good condition, clean it in soapy water and rinse it until the water runs clear.
- Squeeze the filter and allow it to dry.
- Lightly saturate the foam filter in clean engine oil. Squeeze to remove excess oil. (Note: Don’t add oil to a pre-filter used with a paper air filter. This will damage the paper filter). Consult your operator’s manual if you are unsure what fluid you should use for your model to coat the filter.
- Install the air filter.
- Reattach the air filter cover.
10. Bad Spark Plug
A spark plug can be faulty and fouled when the tip is dirty, the porcelain is cracked or the electrode is burnt.
SOLUTION: You can clean the spark plug to remove the deposits on the tip. If your spark plug tips are very dark in color or damaged, you must replace your spark plug.
Your spark plug must be properly gapped following the manufacturer’s specifications found in your Black Max operator’s manual.
Starting problems can be caused by a spark plug that is gapped incorrectly or a spark plug wire is loose.
11. Bad Ignition Coil
Before checking for a bad ignition coil, make sure your spark plug is in good condition. The ignition coil provides voltage to the spark plug so it can start the engine.
If the spark plug isn’t able to fire, the engine will not start.
SOLUTION: Check the continuity of the ignition coil using an ohm meter. If you find a break in the continuity, replace the ignition coil.
12. Bad Recoil
The recoil on your mower may no longer be able to start your mower. A rope on the recoil can become unstrung or you may find you have a broken pulley, springs, or clips in your recoil that need to be repaired.
SOLUTION: Sometimes, restringing the recoil is all you need. Other times you will have to replace broken parts in your recoil. Before doing this, price out a full recoil replacement.
Depending on the price difference, it may be better to replace the recoil assembly over tearing it down and replacing broken components.