Mystery hole? 800 hydro-mechanical

Boomyal · Jul 8, 2012

There is a small hole on the underside of what I would call the upper flange on the lower drive. The flange is like a mini cavitation plate and is about 1 1/2 inches above the main cavitation plate. The flange in question has the bolts up thru it that hold the lower gearcase to the upper.

This hole is on the right side, about 1 1/2 inches behind the front edge of the flange. It's just a clean little purposeful hole, maybe 3/32s in diameter that faces straight down when the drive is in the lowered position. It has been weeping a small amount of drive oil, all winter.

The outdrive has been in the up position and I wasn't sure where the oil was coming from. I scrubbed the drive clean and rechecked for evidence. That is when I saw a little trail of clear oil coming from that hole.

What do you suppose the hole is for and why would it be seeping?

Nivekt · Jul 8, 2012

Re: Mystery hole? 800 hydro-mechanical

Its funny you ask this because I just drained and filled all of my gear case housings and also noticed this exact little hole weeping oil. I hope someone knowledgeable chimes in...

Boomyal · Jul 8, 2012

Re: Mystery hole? 800 hydro-mechanical

I purloined this photo off of a previous iboats post where the question was never answered. Note that hole in question is right above the fill plug of the lower gearcase.

Boomyal · Jul 8, 2012

Re: Mystery hole? 800 hydro-mechanical

<bump> any experts out there?

Reinell-BRXL-191 · Jul 9, 2012

Re: Mystery hole? 800 hydro-mechanical

I think no one wants to answers for a few reasons... first, the hole is a weep hole for water, they drilled them in to the castings to let water out where it accumulates. Second, there should be no clear oil anywhere in that unit... so, if it's leaking clear oil, everyone is wondering why? Third... if it's leaking oil, then it would be assumed the upper to lower gasket has been breached, and you might have water in the units and it should be checked... so.. clear oil??? You got me coach!

southkogs · Jul 9, 2012

Re: Mystery hole? 800 hydro-mechanical

Not quite sure that I entirely agree with the above, but I am far from an expert. I'm thrilled when I see clear oil anywhere in my unit. I'll take it over the milky stuff any day

I'd be surprised if it's a weep hole for water from the lower - stringers rely on being submerged too much, and it's at the top of the case.

Though I wonder if there is a cavity at the ventilation plate that needs drained off?

I keep forgetting to look at my electric shift and see if it's there on mine, but I don't remember seeing a weep hole of any kind in that spot.

I can't find anything about it in the manual that I have (includes the 800).

Help us Howard Sterndrive ... you're our only hope

Reinell-BRXL-191 · Jul 9, 2012

Re: Mystery hole? 800 hydro-mechanical

When I think of clear, I think of oil that is devoid of color - like mineral oil or the like.. if he meant something else, then I retract my statement

Nivekt · Jul 9, 2012

Re: Mystery hole? 800 hydro-mechanical

I took my boat out today and when I pulled her out of the water there definitely was water weeping out of that hole. The odd thing though is that last week when I was filling up the upper gear case housing, I noticed that fresh/new oil was weeping out of that little hole on the lower? Basically just one little drop that came out and ran along the housing. Weird.

southkogs · Jul 9, 2012

Re: Mystery hole? 800 hydro-mechanical

Reinell-BRXL-191 said:
When I think of clear, I think of oil that is devoid of color - like mineral oil or the like.. if he meant something else, then I retract my statement

I was more playing around with ya' ... keeping water outta' my stringer drive is kind of a constant battle for me.

Boom - I checked my electric shift and it does not have the hole. I'm wondering if it's related to the mechanical shift. I think the "stuff" for that sits toward the front of the drive.

Boomyal · Jul 11, 2012

Re: Mystery hole? 800 hydro-mechanical

Surely someone must have one of these drives apart so they could look at where that hole goes? I am pretty certain that the later full mechanical drive has the same hole so that would make it from about 1978 to 1985.

Boomyal · Jul 15, 2012

Re: Mystery hole? 800 hydro-mechanical

If I bump this often enough, someone with the answer will stumble upon it.

Reinell-BRXL-191 · Jul 15, 2012

Re: Mystery hole? 800 hydro-mechanical

I have a 91 clutch dog cobra.. and it has the same hole.. it is a water weep hole for water that gets in to the flange before the gasket otherwise the water would just sit in there unless you kept your drive raised all the time... trust me, the hole is supposed to be there... I don't have any oil coming out of mine - are you 100% sure it was oil, and not exhaust soot / water mix?

Boomyal · Jul 15, 2012

Re: Mystery hole? 800 hydro-mechanical

Reinell-BRXL-191 said:
I have a 91 clutch dog cobra.. and it has the same hole.. it is a water weep hole for water that gets in to the flange before the gasket otherwise the water would just sit in there unless you kept your drive raised all the time... trust me, the hole is supposed to be there... I don't have any oil coming out of mine - are you 100% sure it was oil, and not exhaust soot / water mix?

Yep, it is oil. It's been weeping all winter and the drive has not seen any water for two years now. It has been idle in the tilt up position. I have not lowered the drive, as of yet, to check the oil levels. Maybe that will tell a story. The hole is in the lower drive flange but I do no know which case the oil is coming out of.

Mystery hole? 800 hydro-mechanical

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