Table of Contents
What does flywheel key do?
A soft key allows the flywheel to move on the crankshaft when your mower blade hits a tree root, an old stump, a large dried clod of dirt, etc. If the mower blade is loose, that will cause enough shock to shear the flywheel key, too.
What is a flywheel key in a lawn mower?
A lawn mower flywheel serves several purposes. The flywheel key (sometimes called a shear pin) is a rectangular piece of soft metal that keeps the flywheel in alignment with the crankshaft. The key shears if the mower blade strikes something immovable, such as a tree root or large rock.
Why is my riding lawn mower revving high?
Airflow Issues A lawnmower that hunts and surges may be experiencing something as simple as an airflow issue. If the air that the engine requires to run is blocked, especially sporadically, it can cause the engine to slow down. When the blockage moves or clears, the engine may suddenly rev up in response.
How do you check a flywheel?
How do I check and inspect the flywheel key for replacement? Inspecting Flywheel and Keyway Check for cracks, broken fins and crankshaft damage. Replace if you find such damage. Inspect the keyway and flywheel for damage. Slight burrs may be removed with a file. Inspect the flywheel key.
How do I know if my riding lawn mower is locked up?
Following are the signs that your lawn mower engine is seized. Engine sounds rough. Engine does not start. Blades do not move and are stuck. The cylinder and piston are fixed. Low oil level. Deteriorated fuel quality.
How do I know if my flywheel is bad on my lawn mower?
If the flywheel key shears slightly, the engine runs rough or misfires. If the key breaks, the lawn mower stops running and won’t start. When you try to start the engine, the starter rope might jerk back.
How do you check a flywheel for damage?
If your flywheel is going bad, a smooth pedal is not what you will feel. You may feel vibration as soon as you place your foot on the clutch or when you press down on the clutch. The vibration tends to get stronger as you push on or engage the clutch pedal.
What is the gap between ignition coil and flywheel?
Replacing Ignition Coils or Armatures An ignition armature must be set at a precise distance from the flywheel. Your engine repair manual will provide the proper gap for your engine. Common armature gap ranges are . 006 – .
How do you test a flywheel magnet?
Be sure the magnet you are testing is rotated away from the magneto when testing takes place. Hold the screwdriver against the magnet, if the magnet pulls the screwdriver in, the magnet is fine. If it seems weak or does not pull the screwdriver in, the magnet needs to be replaced.
How many magnets does a lawn mower flywheel have?
There is only one magnet in the flywheel. The other piece of steel is a counterbalance and may have only picked up some residual magnetism. If you’ve got strong magnetism in the one piece, your flywheel is good. It’s possible that your ignition coil is bad.
How do I remove a sheared Woodruff key?
Remove the Woodruff key. Try tapping down on one end of the key with a hammer and nail. Rapidly heating the key with a blowtorch and letting it cool can help loosen it. Remember that these keys are cheap and readily available online or at hardware and auto part stores, so causing damage to it may be necessary.
How do you put a Woodruff key on a crankshaft?
When installing a woodruff key, first press it into the semi‑circular groove milled into the shaft. Next, align the top, flat portion of the key so that it is parallel with the host shaft. During installation, woodruff keys will sometimes slip out of their groove as the mating component is pressed on.
What causes a lawn mower engine to lope?
Problems in the Fuel System The cap on your mower’s gas tank is vented with a small hole. Surging is also caused by water that got into the fuel. A mower left in a heavy rain or condensation on a hot summer day can choke the engine. Empty the gas tank, properly dispose of the old fuel and try a fresh batch of gasoline.
What causes a lawn mower engine to pulse?
The most common reason for a surging lawn mower engine is a blockage in the fuel supply, but there are other possibilities: Bad gas. Bad spark plug. Dirty / faulty carburetor.
Why is my lawn mower not running smoothly?
Causes: If the engine starts, but does not run smoothly, it means that the spark plug and ignition system are in order and you need to look elsewhere for the source of the problem. The usual culprit is air intake or fuel system related.
What does a loose flywheel sound like?
Loose flywheel or flexplate bolts make a rattling or knocking sound that changes with engine speed. It’s heard behind the engine, where it mounts to the transmission bellhousing. If there’s a rattling or knocking sound after an engine has been removed and replaced, the flywheel or flexplate bolts may be loose.
