Author Topic: Merc 90 i6 help  (Read 150 times)

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Offline pyro225

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Merc 90 i6 help
« on: December 07, 2017, 02:28:49 PM »
Hi I have good compression on all cylinder but water in c3 plug - have been researching and water jacket comes up - anyone show me what that is that I need?

Thanks!


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Offline Hyperacme

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Re: Merc 90 i6 help
« Reply #1 on: December 08, 2017, 08:24:44 AM »
 Corrosion from salt water ?
Gregg
'76 CV16

Offline Plugcheck

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Re: Merc 90 i6 help
« Reply #2 on: December 08, 2017, 09:07:04 AM »
We had a similiar issue with a 115 tower of power, water came out around spark plug.  The gasket had failed.  Bad news was the water had made it's way into the cylinder and corroded the cylinder.   If you can't tear it down soon, pull the plugs and get the cylinder oiled to prevent further damage.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project, gps 85 mph (on trailer)
1989 Lowe 200 Redneck fishin Toon

Offline pyro225

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Re: Merc 90 i6 help
« Reply #3 on: December 09, 2017, 11:42:52 AM »
Hi all - it was in salt water prior to my ownership but was flushed every use and had low hours... planning a tear down soon but was just going to do all the gaskets and water jacket but didnít know if you can identify it being bad?


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Offline pyro225

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Re: Merc 90 i6 help
« Reply #4 on: December 09, 2017, 05:37:51 PM »
Also if the cylinder is corroded what can you do?


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Offline Plugcheck

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Re: Merc 90 i6 help
« Reply #5 on: December 09, 2017, 07:54:55 PM »
If the engine turns, that is a good sign.  Some fogging oil or similiar to displace any moisture.  Tim (Makinwaves) had a TOP 115 that had the same issue, several months went by and when it came time to work on it, it was locked up from corrosion in the cylinder.  Just trying to help you avoid a bigger issue.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project, gps 85 mph (on trailer)
1989 Lowe 200 Redneck fishin Toon

Offline Hyperacme

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Re: Merc 90 i6 help
« Reply #6 on: December 09, 2017, 07:56:51 PM »
Friend of mine had a lot of problem with bolts breaking off, while trying to dissemble his I6 Merc used in salt water.
 
Gregg
'76 CV16

Offline Retro Performance

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Re: Merc 90 i6 help
« Reply #7 on: Today at 09:36:55 AM »
Does this engine have a one piece block? In other words the cylinders are part of the block and the water jacket bolts on to allow cooling water to flow around cylinders? If that is true than water can only enter cylinder if a hole or crack exists in the block? Is number three the only one with water? Are you seeing water on the spark plug or evidence of steam cleaning on the piston? Would it  be possible for the water to be coming in thru a leaking exhaust plate gasket or maybe damage to the exhaust cover/plate from corrosion? I think you can pull the exhaust cover without removing the powerhead but like Hyper said, be ready for bolt issues.

Offline Hyperacme

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Re: Merc 90 i6 help
« Reply #8 on: Today at 01:35:54 PM »
Most bolts broke off on (#20 in diagram) exhaust manifold cover.
Gregg
'76 CV16