Want this question answered?
Our Techumseh 8HP has a Champion J8C
On a valve-in-block 8HP with an RJ19LM or equivalent plug, it is 0.030"
I have an early 90's 2cyl, 8hp, 2-stroke and the gap is .040.
Briggs straitton
First change the oil. Then before trying to start squirt someoil (about to table spoons) into the spark plug hole, replace plug and try starting.
Surging is often fixed by replacing the fuel filter. A simple job and most small engine shops will have the part.
318cc. is 8hp. 305cc.is probably between a 6 to an 8hp.
What year is the 8hp Mercury outboard with serial o6156590 ?
some sites say 1952 ,others say 54, and that model# is a 7.5 not an 8hp
Anywhere from 0.040 of an inch to 0.050 of an inch will be acceptable. The gap is not that critical, the wider the gap the less chance for carbon deposit within the electrodes. The high voltage circuits does provide enough energy to generate a blue spark accross the mentioned gaps. Do not dwell on the subject. Gap both plugs the same and enjoy your Merc. Please use high quality oils and gas, little engines deserves the best. Pops D
8hp-14hp
1992