If you don't see a spark on the tester, there may be a problem with the ignition coil of the flywheel to which it's attached. The ignition coil doesn't frequently develop problems, but the connection between the flywheel and coil or between the starting pulley and flywheel can wear out, and the coil may not be turning.
One may also ask, what causes no spark to the spark plug?
Loss of spark is caused by anything that prevents coil voltage from jumping the electrode gap at the end of the spark plug. This includes worn, fouled or damaged spark plugs, bad plug wires or a cracked distributor cap.
Accordingly, how do you check a spark plug on a lawn mower?
Regarding this, how do you check a lawn mower Magneto?
Holding the plastic handle of the screwdriver, bring the metal area of the screwdriver close to a metal part of the engine, being careful not to touch it. Have someone start the mower. If you don't see a spark between the screwdriver and the engine, the magneto is bad.
A dirty or fouled spark plug can cause your lawn mower to not start. It can also work itself loose, causing issues. If the spark plug appears to be seated correctly but the engine doesn't start, a new one may be in order. For a few dollars, this easy fix can get your small engine working again.
Bad grounds can cause no spark issues though. It can cause the ground to ground through the ecu frying it. If you get a single spark when turning on the ignition then nothing when cranking it's the ecu. It's a really good idea to go over all your grounds on a regular basis anyway.
If the spark is still weak after replacing the whole ignition system, then the normal size wiring or connector to the coil may be corroded or damaged somehow. The other real longshot is that the grounding strap between the engine/trans, body, and negative battery terminal is corroded/worn/damaged.
No it would not be the crankshaft sensor. It may be a camshaft sensor or another problem with the fuel system like relay for fuel pump. I recommend having a mechanic like one from YourMechanic diagnose the no start for you.
The most common reason for why your riding mower will turn over but not start is likely due to bad gas or a dirty carburetor. You can usually fix the problem by removing and cleaning out the carburetor and making sure that your gas is fresh. There are carb cleaners you can purchase to help you with this.
Spark plugs that are gapped incorrectly can cause an engine to miss, or run erratically, especially during idle. The incorrect spark plug gaps can cause uneven firing of individual spark plugs and delay engine combustion; both of which can cause an engine to miss or idle erratically.Share to:FacebookTwitterPinterestEmail