Removing or Living With Single Point Merc Draining

[Maclin]

I have a 4.3 with the single point draining, the one with the Blue Knob at front port quadrant of the engine. Also a blue plug to remove on the thermo housing/intake mani. A pic is below, sorry for the bad angle.

I used it last year, temperature here got down to mid teens a couple of times, no block or exhaust manifold damage, so maybe the inside of the block and manifolds are not to the blockage point of rust scaling. Lucky me so far.

I had to replace the water director part way down low, evidently I was not too kind to it when R&Ring the engine to replace the coupler. Nice new $212 part now this year. But...

Does anyone have direct experience with removing this entire system that they can relate here? There are a LOT of hoses, I described it as pandemonium. When you drain, the manual says to make sure a lot of water comes out--I see why, there must be the equivalent of the engine's water capacity just in the hoses.

I just want to go "back" to Drain plugs, is this even doable on this system?. Has anyone done this successfully? Any parts required?

Or do we just have to live with it, and go to the drain plugs, and deal with all the connections and drain there first? Those plugs/locations do not stand out to me especially on the manifolds, a lot if interference from the drain system itself plus other components. Suggestions here are welcomed.

Thanks for reading, looking forward to contributions

 

[Maclin]

Whoa Nellie, PORT side of the engine, yikes.

 

[alldodge]

Have never removed one, but should be easy enough, just need some hoses. Could use your serial number to verify my thoughts

All the items in Green can be removed and plugged. The ones in Blue would be routed to a new thermostat housing except the hose coming up from the drain.

The exhaust manifolds have check valves for draining and can be replaced with standard 90's but if bottom is plugged it would work the same. Need to also route a hose from the cool fuel to the circulating water pump




To compare here is yours
https://www.mercruiserparts.com/bam/subassembly/31502/12839/200

And here is the same motor year with 7 point drain
https://www.mercruiserparts.com/bam/subassembly/31502/12839/210

 

[Bt Doctur]

Have done a few, will have a write up in about and hour when I get back.

 

[Bt Doctur]

Remove A and replace with a section of copper pipe, B can be replaced with copper fittings Remove block drain quick connects ansd replace with drain plugs, either Blue or brass.

. Remove manifold fitting and replace with these

 

[alldodge]

BD question
I know you make the copper fittings to replace the current plastic ones, but why would you install your copper Tee when it can be removed entirely?

 

[Maclin]

Engine S/N is 0M325971

Good stuff so far guys...

 

[alldodge]

Yours is early enough that the standard 4 port thermostat would be used for multi drain. It shows a check valve after cool fuel but not sure it needs it, even though yours has one before the module. Your cool fuel doesn't have a drain like the early ones, so they have install a Tee (861505). The larger circulating hose Tee would need to be replaced on capped/plugged once hose is removed




Current one, so would remove and plug the elbow ports. Remove and plug the lower manifold hoses, or reuse a 90 degree fitting

 

[alldodge]

Lets get GA_Boater to move this to your own thread and we can work on yours

 

[Bt Doctur]

Made the T because it feeds water to the elbow`s with the therm closed

 

[QBhoy]

I’m sticking with mine for now, but by me checking all the individual outlets manually each time, it probably means it’s no quicker a system.
I fill with antifreeze each year so haven’t seen any lumps of rotten engine block yet.
Only fault I can pick with it so far is the valve itself doesn’t seem to positively seat very well.

 

[Maclin]

I removed the block drain hoses this year, prodded and found absolutely no scale or sludge or sand. As far as I know the block is original to the boat, 2002 model. Encouraged by what I did not find, I decided to not check the exhaust manifolds. It is not easy on my boat to get at them, having to remove the screwed-in seat backrest each time. Lots of freeboard in this design, and my arms are not long enough to reach the bottom brackets, painful and frustrating. I have a supply of the stainless screws ready as it is easy to burr one beyond useable on the ones that are hard to reach. It is a chore to align the backrest when putting it back, it does not just rest against the floor. It supports the hatch cover and has to be just right. I usually leave a faint trail of blood. Boats are stupid.

 

[Lou C]

Its still amazing to me, the complexity and cost that Merc added with this to avoid just installing a half closed system as standard equipment. I know heat exchangers are expensive, but that would have been a far better, simpler system overall. And, with a properly set up winterizing tank (ie with a pump to pressurize the flow) you could easily use that to winterize.

 

[Maclin]

Lou C , interesting about the cost comparo with half closed system versus this Single Point system. The water director part is $212 replacement cost, and all the extra hosing/fittings would add up, then the simplicity of a heat exchanger system value-wise is not that far off. Well, seems heat exchanger plumbing would be simpler than this Octopus-esque setup with the Single point, maybe not. And I do not know the cost of the exchanger.

 

[Lou C]

Well you can buy aftermarket closed cooling systems for approx. $1000-$1200, the H/E is the most expensive part, I'm guessing that Merc is saving something like $400-$500 by using the single point drain vs closed cooling. What they are missing is this:
every boater who had one of these, or the old systems where you must crawl around and strain you back, knees, etc to get plugs out...has said to themselves...I'm never buying another of these !@#$% things again....and they go and try a modern outboard and realize....that while they are more expensive they are better in many important ways. Self draining, low maintenance and safer. Next time I'll gladly pay the cost. Outboard all the way.