The spark plug gap for a 2003 Mercury 125hp outboard motor is .040"
spark plug gap for a 1996 mercury 30 hp outboard motor?
What is the spark plug gap for a 9.9hp mercury outboard motor
0.020 in.
.020
.040
NGK BPR6HS-10 spark plug. Gap is .040
The points gap on a Merc 40 4hp is .020
A Mercury outboard will run well with a plug gap of .035 - .040 in.
40
Set the gap at .035 in. for a 115 Mercury.
The maker points in a 1967 model, 110 Mercury outboard, are gapped to .020 in.