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2004 Honda bf135 milky gray oil

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Jacob P

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Motor never ran hot or lost any power no smoke found contaminated oil while getting ready to flush the motor. Just recently purchased boat after it has sat up for 2 years exposed to the element wondering if it could head gasket issue even without performance symptoms?
 
Hi Jacob,

I don't know that model outboard so keep that in mind.

Many engines have head gasket failures with no obvious performance issues so, yes, I would say the head gasket could cause water in oil with no power loss.

Did the contamination happen pretty rapidly? If so, that might indicate a head to block sealing issue or....worse.
It being used, you have no way of knowing if it was ever overheated in the past. Although, if it's compatible with the Dr.H scan software you might be able to find out. I don't know if that's possible.


I do see something in the parts diagram that piqued my curiosity and that you may be interested in.

This outboard has the thermostat housing cast on the chain case cover which is a bit unusual to me. It also has an "optional" thermostat housing cover and seal as well as what looks like an added spacer as part of the option.

Compare items 24 and 26 in the link below to items 25, 27 and 23 in the link below:


The interesting thing about that "option" to me is two fold:

1. The thermostats are the same for both the "original" and option so the option doesn't seem to be an accommodation for a different set of stats.

2. That spacer increases the height of the chain case. So, it's not solving a clearance problem in the engine bay. As a matter of fact, I will bet that the "optional" tstat cover (item 25) has a lower profile than the original (item 24).

That makes me think that the spacer is altering the internal clearance inside the tstat housing for some reason but the reason isn't for "optional" or "taller" thermostats.

That raises a suspicion for me.

I note that the chain case cover is made of thin cast aluminum.

If something were rubbing against that aluminum because of vibration could it eventually rub through and create an issue? Like water and oil mixing? I don't know.
But....it might be something worth investigating by looking underneath the thermostats.

Just an idea.

Working on outboards we're all at a disadvantage because we can't easily pressurize the cooling system to test for internal leaks. I wish I had a solution but I don't.
Sometimes you can identify water intrusion into a cylinder by closely inspecting the spark plug. A plug that looks much different from the others, especially if it has a "cleaned off" look, could indicate a water in cylinder condition.

Good luck.
 
Rare for Honda 135 double lined stainless head gasket to go bad. Do a compression test? start with bottom cylinder that's where they usually blow. if compression is low like 50 psi there is a chance the head gasket over headed and head warped. but If compression is still good 150-225 could be in the chain case when it meets block below thermostats has rotted thru or in the head where it meets the exhaust manifold cooling passageways. If good compression might be reparable.

If you have no compression a pin hole in combustion chamber of head you can pull the plug and turn over engine with flush hose attached you'll see water drops come out of the spark plug hole. Really best in this situation to replace the whole head with the one that comes with the valves included then you will get long term use out of it. In mean time drain engine of milky oil put really cheap oil in it and run engine with no flush hose 15-20 seconds til it feels hot, drain that out and put more cheap oil in it . run it again with no flush hose 15-20 maybe 30 second. this should keep inside of engine from rusting. Do not just drain milky oil and let it sit it will lock up. With the age of a 2004 once you get the head off if the piston liner area below head gasket is corroded and you can see side of piston liner the block is shot as new head gasket will likely not hold.
New head will run $1500-1800 and $125 head gasket and probably about 8-10 hrs labor tear down and reinstall new head. lot of money to put in a 2004 engine. But if you have some compression, it might be worth price of a tear down to see if its repairable.
 
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