What is the spark plug gap on a Craftsman lawn mower?
Flathead Engine Spark Plugs & Gaps
|Replacement Part Type||Replacement Spark Plug Options by Briggs & Stratton Part Number||Spark Plug Gap|
|"Surefire" RJ2YXLE in Craftsman Smooth Start (MRS) lawn mower||591040||.030”|
In this manner, 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.
The Craftsman 4.5hp mower uses either a Champion model RJ19LM or J19LM spark plug, or equivalent, with the gap set at .
Likewise, 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.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.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.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.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.