What is the size of the gap on an echos spark plugs

.40-.45 should be fine.

Most modern spark plugs are pre-gapped. As long as you have the correct plugs for that vehicle and you have not changed the gap, you can fit them straight out of the box without setting the gap.

Most cars have different spark plug gaps but can be the same in some cases. Under the hood of your car will be a white sticker around the radiator or shock tower area that will have information about the engine size, the car year, most times spark plug gaps, and other emission related things. If you do not find the spark plug gap but do find the engine size (written as liters - ex: 2.5L), call any parts store and they can give you the plug gap for your engine/car.

I think it's 0.28

Spark gap is the gap between the electrode and the arm that is needed to a specific size per vehicle and engine size. If this gap isn't correct, you may have problems with missing in the engine. To find out what the gap size is for your vehicle, you can go to your local auto parts store like Autozone and either buy the repair manual for your vehicle or call them and ask them what it should be; they can always look up that information in their systems.

the gap is 0.044

Standard plug gap = 1.15-1.25 mm {0.046-0.049 in}

Spark plugs do not need calibration!! Although it may need gapping which requires a gapping tool such as a filler guage!! Check your local autozone for this tool and gapping specs for this vehicle!!

buy a spark plug gapper at the auto parts store they will be able to tell you what gap for your vehicle