Regarding this, are all lawn mower spark plugs the same?
Yes there are different plugs for different engines. Usually you need the engine model on your mower, and take in the old spark plug to the hardware store. Ask for someone to help you find the right spark plug and tell them your engine model and mower model.
Considering this, what size thread is a lawn mower spark plug? The thread sizes of lawn mower spark plugs are different from those of automobiles spark plugs. Ideally, most automobile spark plugs use a thread size of about 14mm thread why those of lawn mower range between 10 to 12 mm.
Its center electrode should have a flat top. If its top is rounded, then the spark plug must be replaced. Look for cracks or chips in the spark plug's porcelain sheath as well as pitting on its firing electrode.
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.
Typically, the consensus among the mechanical engineer community is that a spark plug for a lawn mower will last up to 25 hours of use. Some users simply prefer to replace it every mowing season as a part of their yearly lawn mower maintenance.
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.
Spark plugs aren't universal; you have to make sure that you buy one that fits your mower. ... If you no longer have the manual or the number has rubbed off, you can always remove the plug first and take it to AutoZone with you.