Special tools
Marvel
Mystery Oil - small can
Medicine dropper, measuring spoon or burette
Note: A burette is much more accurate but also much more expensive,
if you are trying to get to the last 0.1 cc of accuracy use the burette.
The medicine dropper should be good enough for most racers.
- Remove the spark plug
- Make sure the engine is level.
- Rotate the engine using the pull cord so that the piston is below top dead
center on the up-stroke.
- Measure 7.5 cc of Marvel Mystery Oil in your medicine dropper or spoon.
- Pour the oil into the spark plug hole, being careful that it all actually
goes in the engine.
- Observe the spark plug hole while slowly pulling on the starter cord to
move the piston to the top of the cylinder.
- If the oil does not come over the top of the spark plug hole your
combustion chamber volume is greater than 7.5 cc and legal.
- You can turn the engine upside down to drain the oil out, or just leave it
in there when you are done. It will slowly drain to the crankcase and
be burned the next time you start the engine.
