Home › Forum › Ask A Member › 1934 Johnson A-70 › Re: 1934 Johnson A-70

#63753
Anonymous

    This motor is a vacuum/pressure cooling system. When starting motor on boat you must go to max. engine speed to purge air from the cooling system. The motor will not cool in a tank or barrel. Touching the side of cylinder case on the opposite side from the muffler should be warm but not hot.