Re: plugs 1972 chrysler 55hp
If your 72 is not Magnapower, but either magneto or battery ignition, you should NOT be using surface gap plugs. The ignition does not put out enough voltage to fire these plugs at idle. Go to the regular plug and you should have no trouble. Only Magnapower ignition systems use a high enough voltage to fire the surface gap plugs. Surface gap plugs are much colder and more prone to foul than regular plugs.