Mercruiser 140 Exhaust Riser Drain Plug

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Hi there. Just picked up a new to me 1980 Sylvan with a Mercruiser 140 in it.
It's starting to get cold here at night so I'll be draining it after every use.

The Exhaust Riser drain plug is missing and replaced with a bolt. The manifold plug and block petcock are fine though.
I don't want to remove the bolt in case it opens up a can of worms I can't deal with right now.
I've got a lot of things to check out/fix on this thing before winter arrives shortly.

Is there an alternate way to drain the riser, or is it even necessary?

thanks
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
usually no, unless the riser uses a block-off plate and has a hose going to it. Most 120-140 3.0L don't have a drain on the riser/elbow, just the manifold drain
that drains both the manifold and the riser/elbow. Plus it should not have a bolt in it ,wrong thread.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Thanks, good to know. No hose going to it.
My older 140 has a drain plug (and no hose). But I could never figure out why it needed draining.
PO must have lost the drain plug and "plugged" it with a bolt.

I'll carry on with other pressing matters then, like hooking up the blower and getting the bilge pump going!
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,470
Thanks, good to know. No hose going to it.
My older 140 has a drain plug (and no hose). But I could never figure out why it needed draining.
PO must have lost the drain plug and "plugged" it with a bolt.

I'll carry on with other pressing matters then, like hooking up the blower and getting the bilge pump going!

Ayuh,.... Many times there's another drain, exactly opposite side, a twin,....
 
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