18hp tohatsu racing head

[tsrt]

New custom made tohatsu 18hp racing head, center hole plug, need an idea what is the correct squish band?

[Fast Fred]

i don't know what stock is, to get that measurement (stock or factory) take a piece of tin and lead solder, make a hook, pull the plugs, stick it in the plug hole in line with the wrist pin, turn the motor over by hand till the piston gets up against the solder (make sure the solder hook goes all the way to the side of the cyl) turn it through squishin the solder. pull it out and measure it .
you want a POSITIVE squishband or Merc says a NEUTRAL but thay run flat top pistons. from the inside of the squish (spark plug side) you want .032-.040, as you move out to the fire ring of the head it should taper down to say .015-.018

[tsrt]

What about 30hp 3 banger yammie, is it still the same process and measurement?

[Fast Fred]

50%tin 50% lead solder. yes the same for all 2 stroker modas