older mercury part?

[cfish]

hi all new to this form i have a older mercury 9.8 merc 110 serial number 2125270 dont know year the and the push button stop switch is broke and i cant find a new one. if i would connect the wires to a toggle swithch from push button stop switch would that effectivly stop motor? iam also looking for what kind of spark pugs can use and part number.

[boats.net]

It's a 1967 model, yes any off/on switch will work.
Spark plug is AC #40FFK

[cfish]

Spark plug gap

Today I got nkg b7hs what's the gap it should bet set for for this 9.8 merc I tryed .30 gap changed to .10 after pulling starting wouldn't start

[boats.net]

The gap should be 0.030.

[cfish]

The gap should be 0.030.

I set GAp to .030 and pistion hits the top of spark plug making it .010

[boats.net]

Then you have another problem, spark plug should not be hitting, no matter the gap. The AC 40FFK is the correct plug and 0.030 is the right gap. The only thing that comes to mind is someone has altered the engine.

[cfish]

How can I mesure the gap inbetween piston and cylinder head to get right size spark plug

[boats.net]

You would need to clay the combustion chamber, this requires experience. I suggest you take to an authorized Mercury dealer.