Spark Plug Gap?

fastmodena

Recruit
Joined
Jun 10, 2010
Messages
2
I have the small 5hp Briggs & Stratton 4 stroke. I just bought an NGK Iridium plug for it and NGK specifies a .030 gap.

Briggs & Stratton manual says 0.51MM (0.20in).

Do I go with what Briggs says, or NGK? My thought is what Briggs specifies for this motor.

Is the NGK .030 in .in or mm? Their website does not specify. THANKS!
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Spark Plug Gap?

Lets try a little deductive reasoning with this problem.

1) .51 mm is the same as 0.020 inches as stated in the Briggs manual,
2) Your question is if .030 is in mm or inches?
3) It therefore stands to reason that the relationship between .030 mm and .51 mm would be virtually no gap if 0.030 was in mm as this would represent about 17 times less gap and you know that can't possibly work.
4) Therefore 0.030 must be "inches".

If only we used the metric system across the board life would be so much simpler.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Spark Plug Gap?

Nobody said it was stupid. The only stupid question is the one that doesn't get asked.
 

Lion hunter

Lieutenant Commander
Joined
Apr 9, 2005
Messages
1,529
Re: Spark Plug Gap?

99.999% of B&S motors are .030 gap. But there are a few that are .020. I would guess that NGK is wrong.
 
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