Reply To: 1968 Johnson 40hp overheating

[lindy46]

Well the poppet can’t completely seal as there is a notch in the hole in the bottom of the housing to let water drain. Protects against winter freezing. So I took a different approach and blocked the hole in the bottom of the housing, left the thermostat out and ran the motor. Water immediately gushed out the exhaust relief hole on the back of the leg. Then the water flow slowly dwindled until it stopped. Let her set awhile and repeated the procedure – same thing – water gushing, slowly dwindled and stopped. When water stopped flowing the head again was hot enough to boil water. I’m at a loss.