Merc 50 hp water leak

[Ticat]

I have a Merc 50 hp with a wa

I have a Merc 50 hp with a water leak. There is a small manufactured hole just to the left of the top cyclinder sparkplug. Can someone assist me in determining if this is a winter plug (frost plug) and whether it requires a brass screw. serial number on the motor is A702214. Would also help if some could determine the year of this motor by serial number. the motor has been sitting outside for several years in Canadian winters and thought maybe the plug had blown if water had been left in the power head.

 

[tonyob]

"Ticat,

The hole you are re

"Ticat,

The hole you are refering to is intended for a water pressure gauge. You can plug it with just about anything, but I would avoid brass because of the possibility of electrolysis.

The parts book shows the fastening as an ordinary pipe plug.

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