Johnson 90 j90tlcos leak

jetterbug

Petty Officer 2nd Class
Joined
Jul 12, 2011
Messages
133
IMAG0402.jpg

I'm thinking I've got a major problem. I'm trying to get this 90 going with no prevail, and I see a leak below the flywheel portside. Is this a head gasket? Looks like bubbles coming out
 

jayyyy

Seaman
Joined
Jul 17, 2011
Messages
52
Re: Johnson 90 j90tlcos leak

Sounds like a possible crankcase leak. Hopefully not.
 

jetterbug

Petty Officer 2nd Class
Joined
Jul 12, 2011
Messages
133
Re: Johnson 90 j90tlcos leak

I took the coils off to clean mating surfaces. Found one that was in need of attention and one that the ground clip broke off as soon as I took it off. Replaced bad one and went to crank over and I noticed a few small bubbles come out.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Johnson 90 j90tlcos leak

Crankcase leak or side cover gasket leak.
 

jetterbug

Petty Officer 2nd Class
Joined
Jul 12, 2011
Messages
133
Re: Johnson 90 j90tlcos leak

Crankcase leak or side cover gasket leak.
It appears to be crankcase leak. Is this a job many of you have done? I have not noticed this since yesterday. I've been working on this thing for a month now, replaced water pump, coils, wires plugs and now this...??. Is this Murphy at his finest? So should I attempt to fix, or look for another OB? Thanks
 

etracer68

Ensign
Joined
Oct 11, 2009
Messages
906
Re: Johnson 90 j90tlcos leak

I would say the picture is of the right (starboard side).
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: Johnson 90 j90tlcos leak

Spray some soap water and se if it is the crank case pr the by-pass covers leaking.
If crank case, you are in for a complete tear down of the power head. Done that a lot of times!!!
About 1 days work depending on your skill and tools and corroded bolts!!
You might as well order a complete seal kit and o a resealing of the power head at the same time.
 

jetterbug

Petty Officer 2nd Class
Joined
Jul 12, 2011
Messages
133
Re: Johnson 90 j90tlcos leak

Yes its starboard side. I misspoke earlier. HOW does this happen? I it something I did or couldve prevented? I thought I was getting so close. I just got this mounted on boat...do I need to take back off or can I do on boat? What special tools required? Where would you recommend to get complete gasket set? Thanks again
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: Johnson 90 j90tlcos leak

What is the usual 'cause' is lean burning resulting in what is called 'crank case combustion', some call it sneezing engine for short. The combustion on top of the piston goes by the intake ports and continues BELOW the pistons. Might be due to faulty thermostats, clogged carbs or whatever gives a lean mix. Sfter some time the Gel Seal between the two halves burns out.
You need a torque wrench, good socket set and some general tools, but not much more.
Parts you may get from this site, Marine Engine, BRP dealer or any Sierra dealer.
In addition to the gasket kit you need a tube of Gel Seal II from a BRP dealer and I recommend a can of Sealing Compound as well.
http://www.marineengine.com/parts/j...rer=Evinrude&section=Cylinder+&+Crankcase

However perhaps the most important is an OEM (original) Workshop Manual which I know Marine Engine has. No Seloc or online!!!!!!
 

jetterbug

Petty Officer 2nd Class
Joined
Jul 12, 2011
Messages
133
Re: Johnson 90 j90tlcos leak

What is the usual 'cause' is lean burning resulting in what is called 'crank case combustion', some call it sneezing engine for short. The combustion on top of the piston goes by the intake ports and continues BELOW the pistons. Might be due to faulty thermostats, clogged carbs or whatever gives a lean mix. Sfter some time the Gel Seal between the two halves burns out.
You need a torque wrench, good socket set and some general tools, but not much more.
Parts you may get from this site, Marine Engine, BRP dealer or any Sierra dealer.
In addition to the gasket kit you need a tube of Gel Seal II from a BRP dealer and I recommend a can of Sealing Compound as well.
http://www.marineengine.com/parts/j...rer=Evinrude&section=Cylinder+&+Crankcase

However perhaps the most important is an OEM (original) Workshop Manual which I know Marine Engine has. No Seloc or online!!!!!!

Haffiman, thank-you. You have been a big help. I will make sure it is NOT the bypass cover that is leaking. They are too close together to see for sure.
 
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