homepostsWhat is the spark plug gap on a Craftsman lawn mower?

What is the spark plug gap on a Craftsman lawn mower?

Dennis WaldenSep 13, 2021

Flathead Engine Spark Plugs & Gaps

Replacement Part TypeReplacement Spark Plug Options by Briggs & Stratton Part NumberSpark Plug Gap
"Surefire" RJ2YXLE in Craftsman Smooth Start (MRS) lawn mower591040.030”

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Just so, what is the proper spark plug gap?

For most racing applications, you usually want the plug gap to be between 0.020 and 0.040 of an inch. Most engine builders seem to settle around 0.035 of an inch. Factors such as the type of ignition you run, cylinder heads, fuel and even timing can affect how much gap will work best for you.

In respect to this, what spark plug do I need for my Craftsman mower? Replacement Plug

The Craftsman 4.5hp mower uses either a Champion model RJ19LM or J19LM spark plug, or equivalent, with the gap set at .

In this manner, what's the gap on a spark plug for a lawn mower?

Setting the Gap on Your Spark Plug

You'll need a spark plug gauge to adjust the gap on your lawn mower's spark plug. Although many small engine spark plugs require a .030 gap, this varies depending on the engine type. You can check this on the engine owners manual.

What happens if the spark plug gap is wrong?

If the spark plug gap is incorrectly set, it can lead to engine issues. The customer may experience loss of power, misfires, spark plug fouling, increased plug wear, or poor gas mileage.

Do lawn mower spark plugs come pre gapped?

Check the gap on the new spark plug before installing it. A new plug will often come pre-gapped to match your specific engine, but use a spark plug gauge to verify that it matches the manufacturer's specifications.

Can spark plug gap cause rough idle?

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.

What happens if point gap is too small?

In short, either too wide or narrow a point gap will cause a misfire under load. I recommend setting your point gap with a feeler gauge and fine tuning with a dwell meter.

Are pre gapped spark plugs good?

Gapping the plugs to your engine's specifications is important to prevent pre-ignition, detonation, fouling and poor fuel economy. Even if the preset gap matches that required by your engine, it is always good practice to physically check the gap as it may have shifted during transportation.
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About The Author

Dennis Walden

Dennis owns a small farm and loves to grill since his early childhood. He’s a professional cook, but hiking and enjoying the great outdoors is his no less favorite part of life.

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