Early 70's 7.5 leaking water from top cylinder

R

Ryche

Cadet
Joined
Jun 3, 2003
Messages
15
I've read a couple other post about this from the search function, but nothing specific on this motor.. I noticed this weekend that my motor was leaking water from the top cylinder and running very rough (i first blamed points)... Now as far as i can tell the water is causing that specific cylinder not to fire. It runs really rough and never gets to full throttle under a load... (would the water cause this problem).. I've read that it could possibly be the water jacket gasket or the water jacket itself.. How will i know wich is the issue.. I've read that i should warm motor up before trying to remove the water jacket bolts.. does anyone else have anything i should know before i attempt to tackle this issue.. thanx in advanced..
 
R

Ryche

Cadet
Joined
Jun 3, 2003
Messages
15
Re: Early 70's 7.5 leaking water from top cylinder

btw its a mercury 7.5.. i thought the year was a 1975, that's what the guy told me when i bought it, but i have points on this motor and i read that points were only up to 73..
 
R

Ryche

Cadet
Joined
Jun 3, 2003
Messages
15
Re: Early 70's 7.5 leaking water from top cylinder

LOL. i should also mention that the water is coming from around the spark plug, not the cylinder itself..
 
Chinewalker

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Early 70's 7.5 leaking water from top cylinder

Whether it's the water jacket cover or the gasket, you have to pull the cover off in either case. Only then will you be able to see which it is. Might be a combination of both. I've had good luck filling some severe pitting with JB Weld and then sanding it down on a surface plate (or any absolutely flat surface). A new gasket is in order in either case. Save the old one as a template and cut a new one. Try to match up the material as best you can with something from the hardware store or NAPA. If you've got a Merc dealer handy you might get lucky if he has a new gasket in stock...<br /> If the water is shorting out the plug, it is indeed possible that that is the cause of your performance issue....<br />- Scott
 
R

Ryche

Cadet
Joined
Jun 3, 2003
Messages
15
Re: Early 70's 7.5 leaking water from top cylinder

Thanx scott.. i was able to get an OEM gasket and am on my way home to mess with it now.. thanx for the response..
 
You must log in or register to reply here.
Top