How Many and Where Are Blue Drain Plugs on Merc Black Scorpion
- #2
Re: Water drain plugs locations on Mercruiser V8. (pics)
I would consider replacing that galvanized street elbow with some brass fittings.
- #4
Re: Water drain plugs locations on Mercruiser V8. (pics)
I remove the drain plugs/petcocks and store them in a baggie as well.
- #6
Re: Water drain plugs locations on Mercruiser V8. (pics)
Im kinda confused, I have the merc 5.0mpi that has the single point drain plug in the front that drains the water out. Does that drain all the water out eventually or do I need to find all these other drain plugs and take those out too? Thanks good info and pics.
- #7
Re: Water drain plugs locations on Mercruiser V8. (pics)
Your call on that, but its only going to get worse with rusting
- #9
Re: Water drain plugs locations on Mercruiser V8. (pics)
Try some moderate pressure and if it doesn't move, leave it be.
If it comes loose, clean up the internal threads and put some grease on the new brass fitting and install and tighten just a bit more than snug.
- #10
Re: Water drain plugs locations on Mercruiser V8. (pics)
The winterizing debate; an annual occurance. I remove all the plugs, hoses and such, and then take off the thermostat housing. This is a good time to check and/or replace the thermostat. I believe in adding the pink stuff - antifreeze - to the system. I pour it in through the open thermostat housing. As it comes out the bottom openings, I reinstall the plugs and hoses and then top off the engine. I do this to prevent further rusting in the block and manifolds. I know air can't freeze, so some people prefer leaving the system empty. But, cast iron can rust when exposed to the damp air of winter. The $25 or so I spend on antifreeze is, in my opinion, worth it. The pink flowing out also gurantees that I got all the water out. On newer Mercruiser engines, look for the drain plug in the "cool fuel" system down in the back on the starboard side. I didn't know about that one until it was posted on the Chaparral Owners Forum. When I removed it, more water came out, even though I had already filled the engine with antifreeze. The 2000 Mercruiser 5.0/5.7 has six plugs. Think spring. Hy
- #11
Re: Water drain plugs locations on Mercruiser V8. (pics)
I put everything back together. To many mice like to get into my engine.
- #13
Re: Water drain plugs locations on Mercruiser V8. (pics)
I agree. I did the pink-stuff-in-the-container-with-the-flusher-hose thing last year and thankfully I had no issues this year. However I did the same thing this year, opened the petcocks and saw NO pink stuff in the water. So I said "not taking the chance" and opened the 2 petcocks in the block and the blue ones in the exhaust manifolds and let ALL the water run out and reinstalled the petcocks. Then I loosened the thermostat housing and poured the pink RV AF (-50) down the thermostat opening in the intake manifold with a funnel. It took less than 2 gallons.
I opened the block petcocks slightly to check for the AF and there it was. The only disadvantage I can see to this is the AF does not get to the power steering system, which needs to be winterized also according to Merc. I may manually disconnect the p/s steering tubes to get the water out and then reconnect them. IT wouldn't hurt to pour some AF down the hose that the freshwater comes in from also and down the hose that goes from the Stat housing to the water pump.
As far as draining the block and leaving it with no AF, I had an overheating problem this year and fixed it by backflushing the block with the garden hose through the petcocks in the block until it ran out the top of the Stat housing. I saw quite a bit of scale and rust come out and no more overheating (Merc Alpha 1, 270 HP) If you've got air and iron, you're gonna get rust. I would not leave it dry, I would definitely put AF in there.
Good luck. 
- #15
The first thing you do is read the Help Tip on top of the page about posting in old threads - This one is 7 years old.
The second thing is live with the missing pics - The pic poster has to pay Photobucket $400 to share pics, not you. Since he last visited 3 years ago, it's not going to happen.
Closed.
Because we have no idea what motor you may be planning on winterizing, start a new thread with the details. Winterizing is one of the most posted thread topics and posts. Lots of help here, just ask.
Source: https://forums.iboats.com/threads/water-drain-plugs-locations-on-mercruiser-v8-pics.434716/
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