'86 Mercury 25hp - Water squirting out of mystery hole

Edgewater37

Cadet
Joined
Oct 6, 2011
Messages
22
I recently purchased this 1986 25hp Merc outboard. The engine seems to be running fine, however when I looked at thestream of water coming out of the back port of the engine I noticed that below it, on the small cowling that surrounds the drive shaft area there was water coming upward and out of it, from what I think is an excessive amount. I took the motor to my mechanic and he removed the cowling, and found this hole on the side (See image) He seems to not have ever seen this before and we are stumped. Anyone out there know why this would be there, and if it is supposed to be there, what purpose does it serve? I really don't think water is supposed to be pouring out of it..

small_merc_hole.jpg

Any info or guesses would be appreciated!
 

FLATHEAD MAC

Petty Officer 2nd Class
Joined
May 11, 2009
Messages
116
Re: '86 Mercury 25hp - Water squirting out of mystery hole

might be water tube going from water pump up to powerhead. possible crack or missaligned .when was impeller last changed,?? if unsure would be good insurance to replace it and check the water tube.
 

Edgewater37

Cadet
Joined
Oct 6, 2011
Messages
22
Re: '86 Mercury 25hp - Water squirting out of mystery hole

The water pump and impeller were changed a couple of weeks ago. Like I said, the engine is spitting out water out of the tell tale just fine, after it heats up for a minute. Wouldn't that mean the powerhead is getting cooled properly? Are these holes supposed to be there at all?
 

will941s

Chief Petty Officer
Joined
Oct 1, 2007
Messages
540
Re: '86 Mercury 25hp - Water squirting out of mystery hole

I've never noticed on there before, but I think that is just a empty void in the midsection. Could be a relief hole incase it gets too full of water. On the lower unit, there should be a series is small holes toward the front/top under the anti cavitation plate. I would start by making sure they are not clogged. They act as kind of a drain for the mid section. Does water come from here right after start up, or after if runs for a little bit? If you running it on muffs, and the mid section is filling up with water, check to make sure you have a proper seal on the o-ring for your water pump impellar cup. If thats not the case, then i'm stumped too
 
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