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BF9.9 (1997 model) Gear Housing Oil Leaking

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brianallen

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My gear oil is leaking from one of two openings in the gear house near the gear oil check screw (see the photo). I reviewed a set of shop manuals to determine the likely source, but it doesn’t contain my exact model (I have a BABU1000054).


I was not able to determine which hole the oil came out. I am guessing that these holes allow water to drain. Somehow oil is getting into this area and likely allowing water to get into the gear oil.


Does anyone know where these holes go inside the gear housing? My guess is the one near the edge drains the water area around the shift rod.

Honda BF9.9 (1997) Lower Housing.jpeg
 
These holes drain water to prevent winter freeze up / cracking.-------Your local friendly boat shop can pressure test the gearcase.----That will find leaks.----Or if you are familiar with tools , a seal kit on a 23 year old motor is easy to install.
 
Alan Hicks said:
Is the engine oil level holding OK?
Click to expand...

Yes, I believe it is. Can the engine oil get all the way down to water pump and gear case?

The outside top of the water pump housing looks very clean. If engine oil can into the lower area, I would have expected to see a mess in the area over the water pump.
 
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It's not likely, but it can happen. There's a seal near the lower crank bearing on any 4 stroke. If something is going on there, it would leak down into the exhaust area, which could easily show up at those drain holes.

Another thought might be a something going on with the oil pan (or where this engine stores it's oil), A pin hole cause by corrosion, or possibly a gasket decided to let go on you.

My first move would be to pull the lower unit - as if you were going to change the water pump. Then have a look around. Seldom do you see oil running up hill.... -Al
 
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