Mid 90's 40hp Force water in top cylinder

Joined
Jul 17, 2006
Messages
73
Motor got hot, now getting water in top cylinder. Motor did not score either cylinders surprisingly compression is 140 in both.

Replaced head gasket, exhaust side gaskets thinking maybe something blew.

Any thoughts on where the water may be coming from?

Thanks!!!
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
If there's water intrusion into the cylinder and compression is good, then the other source of water will be the exhaust plate gasket. Time to open and inspect the exhaust plate. Beware bolts are exposed to water and heat, hence are highly corroded. It's not unusual to break one or two in the process. So make sure you soak them well in penetrating oil or liquid wrench before attempting.
 
Joined
Jul 17, 2006
Messages
73
If there's water intrusion into the cylinder and compression is good, then the other source of water will be the exhaust plate gasket. Time to open and inspect the exhaust plate. Beware bolts are exposed to water and heat, hence are highly corroded. It's not unusual to break one or two in the process. So make sure you soak them well in penetrating oil or liquid wrench before attempting.

Thanks but this has been done. Surprisingly the bolts all came out easily. Both gaskets were replaced with new and the exhaust plate did not have holes.

My fear is a crack somewhere that I cannot see. Possible???
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
A crack is possible considering the motor overheated. If both exhaust plate gaskets (there are two of them) were replaced including the head gasket, the only other source of water intrusion will be a cracked cylinder or head, or a warped head.

Personally, I'll ran the motor for a little bit and thereafter cool it down and open and inspect the head and cylinders for cracks or warped head. Usually, you should have some kind of water marks to indicate the source of water intrusion.

You can post pic for additional analysis.
 
Joined
Jul 17, 2006
Messages
73
A crack is possible considering the motor overheated. If both exhaust plate gaskets (there are two of them) were replaced including the head gasket, the only other source of water intrusion will be a cracked cylinder or head, or a warped head.

Personally, I'll ran the motor for a little bit and thereafter cool it down and open and inspect the head and cylinders for cracks or warped head. Usually, you should have some kind of water marks to indicate the source of water intrusion.

You can post pic for additional analysis.

That's what I was afraid of - a crack. It is actually a buddy of mines motor. I have worked on outboards for 25 years, just don't have a ton of experience with Force motors. We had the head resurfaced/cleaned, replaced head gasket and exhaust gaskets like I said earlier. I wondered about the adapter gasket, but then I would think there would be water in the bottom cylinder. Not the case. Its getting enough water in the top cylinder the plug comes out with a creamy colored oil on it and the motor miss fires more often than not.

Sounds like its time for a new motor. Thanks!
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Was working on a 78 50 Mercury.
This kept fouling with fuel.
No matter what I did?
I couldn't get it to run right.

​The owner said figure it out!!

I dismantled the motor.
Looked and looked??
Then I noticed a scratch on the intake side of the middle cyl.
Looked like a screwdriver slipped and scratched it.
Then thinking back: I didn't use a screwdriver when taking apart.
The crack was my problem.

Turns out the owner had over heated and caused the crack.


Take it down and inspect for hairline cracks.
The head is a good place to start??
 
Joined
Jul 17, 2006
Messages
73
Was working on a 78 50 Mercury.
This kept fouling with fuel.
No matter what I did?
I couldn't get it to run right.

​The owner said figure it out!!

I dismantled the motor.
Looked and looked??
Then I noticed a scratch on the intake side of the middle cyl.
Looked like a screwdriver slipped and scratched it.
Then thinking back: I didn't use a screwdriver when taking apart.
The crack was my problem.

Turns out the owner had over heated and caused the crack.


Take it down and inspect for hairline cracks.
The head is a good place to start??



Yes we discussed the head last night. Going to take it off and look at it closer. It was cleaned and resurfaced, didn't notice anything prior to reinstalling, but maybe we will get lucky and find a crack in the head vs the block. Could be a small enough crack to only open under pressure or vacuum.
 
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