Exhaust Leg Drain Cavity

[bobw]

I’m cleaning up the lower unit/gearcase on my 1956 Johnson RD-18 and had a question on what I think is a clogged up drain cavity. The cavity in the first photo is in line with the drain hole in the 2nd photo but the space between them seems to be stopped up/blocked. I assume this is in fact a casting cavity and the drain hole would serve to drain off any water in the cavity. If so, what is the best way to clean out this cavity to ensure proper drainage? I’m hesitant to just start drilling.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

• This topic was modified 5 years ago by bobw.
• This topic was modified 5 years ago by bobw.

[Buccaneer]

On one of my outboards, that drain was plugged up with very hard sediment.
I took a long stiff wire with the end hammered flat like a screw driver, chucked
it in my drill, and eventually drilled it out. Not as fast as a drill bit, but probably safer.

Prepare to be boarded!

[bobw]

Buc,
I’m LOL. I just got done doing the exact same thing! I was looking for some small rod stock I had which I thought I could sharpen a little bit to drill the crap out very slowly. Couldn’t find the rod stock but came across a piece of very stiff wire. Didn’t know if that would work but I filed a point on it and drilled on the debris a little bit, then tapped on it very lightly with a small hammer and it poked right through. It was sure plugged up but flushed it all out and drains perfectly now.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[olcah]

Edited out, problem solved.

[billy-j]

Mine was so plugged up with a hard as a rock cement like mixture of sand and silt that I had to take a small carbide tipped masonry drill and weld on a piece of rod to make it long enough to get down in casting to drill out the sediment and clear the passage.

[joecb]

Yep’ what has been said…. If you can get a 1/4 ” drill bit 12 ” long that works good because the helical flutes help pull out the crud

Joe B

[olcah]

Actually the drill bit needs to be 1/8 inch. Also FWIW the drain hole can be offset from the casing drain outlet so it is possible to drill right past the outlet and not see the drill looking at the outlet. So mark the depth on the drill so you don’t drill past the outlet.

• This reply was modified 5 years ago by olcah.

[bobw]

I poked through the debris with the stiff piece of wire and got some positive drainage established, then cleaned out the rest of the packed sand and dirt with a few shots from my pressure washer. Factory clean and good drainage now.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[chris-p]

There are very often mud dauber nests in there. They can get VERY hard, and require drilling.

Good on you for taking care of it.

Guys that don’t, end up with cracked gearcases over the winter, when the water can not drain out, freezes, expands, and cracks the gearcase.

Critical to keep those clean.

[bobw]

Absolutely. I’ve encountered a little debris in these cavities before but I’ve never had one that was just packed solid like this one was. Knew I had to get it cleared one way or another.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[Author]

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