Single point drain tech tip

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,383
We all know it looked good in design but sucked in application leading to cracked block or manifolds. Unless you collect and measure the water leaving the drain and make sure it adds up to atleast 4 gallons something did not drain. The most likely culprit is the block drains being plugged up. You thought you drained everything but the block did not drain.
To those introducing the AF thru the drive no matter how much you run thru it you only diluting whats in the block.
If you are pouring it in the block and it DID NOT TAKE at least 2 gallons before it ran out the T housing your block did not drain.
The safest way to winterize is to pull the drains and hoses and probe the fittings to insure there open and draining.
I also have had the manifold drain plug check ball fail and a manifold not drain so removing the main hose is good insurance to insure draining

Have a Safe Holiday Season
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,559
Im convinced that the engineers at Mercury that designed the single point and 3-point drain systems have stock in GM crate motors. Good advice BT
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
My old boat never had single point. I'm really gratified to see a solid stream out of block drains done the old reliable way. I'm blessed with great access, at least compared to many setups, especially side by side down in the hole twin cruisers. I'd have full heat exchange systems in any boat with poor access. That's for sure.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,187
My old boat never had single point. I'm really gratified to see a solid stream out of block drains done the old reliable way. I'm blessed with great access, at least compared to many setups, especially side by side down in the hole twin cruisers. I'd have full heat exchange systems in any boat with poor access. That's for sure.
Yep that's the only way with bad access, closed cooling and a remote oil filter mount is how to make I/O ownership bearable as you get older.
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,902
That’s why I had kids, my 15 years old is learning how to do it. I was about 13-14 when I started working on my grandfathers boat.... teach me to work on a boat I can waste a lifetime....
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Excellent.
I always drain using the valve. Then take off each quick connect fitting. Pour in some AF and price it comes out each individual drain at the source. Then you’ve proven they aren’t blocked. Connect it all back up again. Fill to the brim with AF. Block and exhausts until it comes out the drive. Job done.
 
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