What plug do you spark TOO!

[run out]

I have a 250 efi 2 stroke 04 that my mechanic told me way back that these mtr's run better on champion plugs. That for some reason merc mtr's don't like NGK plugs. Well I was in a pinch and could only find 2 champion so I went with the NGK set the gap, torque at 17 foot lbs, and didn't seem to have any trouble yet. " I might be burning more fuel than before" but who knows. any thoughts. This mechanic is not dumb.

 

[galamb]

It depends on the ignition.

If Merc put Champion in "at the factory" (or NGK for that matter) that's what I would run and forget the cross reference to other plugs.

Even cross ref plugs will be "slightly" to a lot different. The ignition was designed with a specific plug in mind - use that.

The smaller, older 2 strokes run better with NGK plugs. The newer computer controlled ignitions were built to a different spec.

Looks like your model came from factory with QL77CC Champions, so that's what the "designers" decided to use - I wouldn't vary from that except in an absolute emergency...