?84 90hp i6 water jacket

pyro225

Petty Officer 2nd Class
Joined
Oct 1, 2014
Messages
191
Hi all I have water in cylinder 3 when I look at the plug... done various tests and it seems the water jacket needs changing from reading... can anyone show me what this part looks like? Some people say just the gasket others say the jacket itself will be warped so that will be needed with the gasket... then I look at water jackets online and some just look like the cover where the plugs go ... and others look like they have rectangular ports... anyone able to tell me what?s correct? Thanks
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
36,033
Answer in detail-----Do you actually have water inside the cylinder ?-----Or is water leaking around #3 sparkplug when motor is running ?------If water is actually getting into the cylinder it can cause major rust damage to bearings in the crankcase and needs to be fixed ASAP.-----That would involve removing the side exhaust cover.----Salt water motor ?
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
Like above, make sure you get the correct diagnosis, if your not sure take it to the dealer/mechanic.
Better get a factory service manual.
Water in #3 is kind of a big deal, if you've never done it before.
You could watch all the you tube videos.
.
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Like above, make sure you get the correct diagnosis, if your not sure take it to the dealer/mechanic.
Better get a factory service manual.
Water in #3 is kind of a big deal, if you've never done it before.
You could watch all the you tube videos.
.

What videos should he watch? Youtube has billions to view!
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
What videos should he watch? Youtube has billions to view!

It seems "watch youtube videos" is his answer. Maybe a stockholder?

A parts diagram is available at Mercruiserparts dot com

A repair manual will be your friend with that motor.
Will have parts diagrams as well.

Factory is nice, but it assumes you have background.

Clymer brand repair manual is easy to follow, and a lot cheaper.
Google "clymer B726" for lots of new and used choices for the manual.
 
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mav6759

Chief Petty Officer
Joined
Jun 25, 2007
Messages
489
I had the same issue with a Mercury 150hp, but I didn't have water in the cylinder, it was coming from under the block... all I had the do is change the water gasket gasket..but to get to the water jacket gasket, I had to replace 2 or 3 other gaskets in the process. But its not to hard...
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Had the same problem with my 1988 after a few years of ownership. Iboats probably sells the water jacket gasket. Being a '84 model and if used in salt water, you may be referring to water inside the cylinder, not water squirting out, visible from outside the engine, while running, from around the spark plug. The gasket replacement is for the latter....water visible from outside the engine.

Your biggest problem in replacing it is getting the SS bolts out without breaking off which is usually the case. I think it was Racerone that posted, years ago, that he grinds the heads off so that he can remove the water jacket cover. Once removed, he soaks the threads with a quality penetrating oil and then removes the bolts with vise-grip pliers. Sounds like a plan as the break is usually right at the block surface because from the outside, (with the water jacket cover still installed) the penetrating oil can't get down into the thread area.

Bolts are SS and "Fastners" company stocks all types if Iboats doesn't have them or your local dealer or NAPA can't get them for you. Run a tap in the threads to "chase" them....clean out the corrosion and I liked to put Blue Locktite (thread sealant) on the bolts prior to installation.....lubricates the installation for better torque setting, locks the bolts from vibrating loose, and helps to prevent further corrosion.
 
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