Rust at the drain plug

[k-nutz]

So I winterized yesterday evening and when I finished I went to drain the antifreeze from the block. All the plugs drained fine except one. When I looked at the plug it had rust staining all all over. I didnt have any bendable wire to run into the hole, and a straight wire wouldn't do the trick due to the y-fitting. My question is, is rust a cause for huge concern at this point since it was just one drain that seems to be blocked? Should I be planning on future maintenance? Since I am not fully familiar with the cooling system, I am wondering if this has anything to do with the manifold/risers? They have never been replaced and it might be time to do so. The boat is a fresh water boat, but the water can get pretty brackish at times.

It was the cylinder block drain plug, the lower plug in the diagram below:

 

[scoflaw]

Rust is normal, it's an iron block. Do get that unplugged

 

[k-nutz]

thanks for the quick reply and putting my mind at ease... It was late by the time I was finishing up and discovered the rust covered plug. I plan to return today to finish up and get into that drain. Glad I found the mercruiser service manual online (very different from the seloc manual) this morning, because I was prepared to remove that y-fitting to really get in there and clean out any rust, but apparently should NEVER be removed.

 

[Lazy Daze]

Yup, normal. A zip tie can usually be wiggled through. When you drained the water out the first time, did water come out of each hole? Or was it blocked then, as well? What does the manual say about removing the adapter? I've removed them before with no ill effects.

Did you make sure to properly winterize the top part of the engine?

Out of curiosity, why remove the AF? If you're using the proper kind, it has corrosion inhibitors in it - without it, you will get more corrosion on the inside. Of course, the wrong kind of pink AF can actually cause corrosion.

 

[k-nutz]

Yup, normal. A zip tie can usually be wiggled through. When you drained the water out the first time, did water come out of each hole? Or was it blocked then, as well? What does the manual say about removing the adapter? I've removed them before with no ill effects.

Did you make sure to properly winterize the top part of the engine?

Out of curiosity, why remove the AF? If you're using the proper kind, it has corrosion inhibitors in it - without it, you will get more corrosion on the inside. Of course, the wrong kind of pink AF can actually cause corrosion.

Good idea with the zip tie, I will give that a shot this afternoon. I had the CAMCO antifreeze with corrosion inhibitors, I picked it up from the marina the week before. Being the first time winterizing I thought I was supposed to drain also after running the pink through. so now I am going to buy another couple of bottles of anti-freeze and do it again this time leaving it in there to sit through the winter.

What do you mean by did I make sure to winterize the top part of the engine? Essentially what I did was run on muffs til I hit operating temp (to make sure the thermostat was open as well, then I switched to antifreeze instead of water through the muffs til I got pink coming out of the exhaust. It took pretty much exactly 5 gallons before I saw pink coming out of the exhaust. Then I fogged the engine, cut it off and then drained the oil.

At the end of the day as I was cleaning up I opened up the drain plugs (because I mistakenly thought I was supposed to) and drained all that was in there. All the plugs poured out pink except the bottom engine plug on the starboard side. The picture from the manual has the caution to never loosen or remove the brass y fitting that is used on efi motors.

The reason I want to go back and do this again is because having seen that there is rust inside the block, it would be good to let the antifreeze sit in there with the corrosion inhibitors.

 

[Lazy Daze]

Don't believe everything you see on Youtube (the bucket method). :smt001 What happened was that you ended up mixing the antifreeze with water. It will always look pink, but you had somewhere between 0% and 100% antifreeze circulating through the engine. Your guess is as good as mine on exactly what % you had.

"Top of engine"... Now, what happened here is that the thermostat may or may not have stayed open as the cooler AF hit it and there would still have been some water trapped in the intake manifold area. Again, it's a crap shoot.

If you want to do the bucket method, you MUST still drain the engine (including the sea water pump). Then pull the t-stat out. Then hook up the bucket and run the engine. Then reinstall the t-stat (and will probably need a gasket). Doing this while at the same time trying to fog (and NOT run out of pink) is kind of a big pain in the butt.

I don't like crap shoots. I like to be guaranteed. In addition to shopwork, I winterize boats on the side. If I'm signing my name to something, I want to be sure it's right. Believe me, time is money - if there was a faster way to do things, AND be guaranteed, I would do it. But I'm not sacrificing quality.

 

[k-nutz]

thanks for the reply. Yeah I was using the "youtube method" but after finding the actual Mercruiser Service manual for my motor it seems as though draining the system first then manually pouring into the hoses is the way to go, and likely a lot easier anyways.

 

[Lazy Daze]

The only 'tough' part, and it's really not that tough - especially on a boat like yours with good engine access - is to remove the output hose on the sea water pump and then 'bump' the engine (flip the kill switch so it doesn't start) a few times to fully evac all the water. Don't forget the fuel cooler plug.

Along with others, I've made many posts about this method. But if you still have questions after searching... I see your signature... --- let me know.

 

[k-nutz]

haha will do, thanks again Dennis, I was curious about how to bump the engine as the tech manual didn't really explain that one, but you explained it in an idiot proof way. I did forget the fuel cooler plug but noticed that in the tech manual while I was reading it this morning. I really wish mercruiser made those easily available, but fortunately I found all of them in an easy location without having to pay for them. Now I am downloading all of them for whatever motors I find myself with in the future.

 

[k-nutz]

Dennis,

The zip tie did the trick. It was perfect. Not to rigid to where it wouldn't make the bend thru the y fitting and firm enough so that the pressure of pushing it in furge knocked away the blockage and allowed a good bit of drainage... thanks alot!

 

[Lazy Daze]

Good - glad it worked for you. In the Spring, I would run the engine for a bit with the block plugs out. Keep poking as the water is draining out. Watch your engine temp, of course, but it's not going to overheat so fast as you'll get in trouble. May not even overheat at idle at all. Turn it off, let it set for a bit and then do it again like that a few times. If you really want to get crazy you can run muriatic acid through the engine, but that's some instructions for another time.

 

[suss1173]

Would it be OK to run it on the muffs for 7-10 minutes to get the t-stat open. Thwn drain the block (trying not to burn your arms) and than run the pink through the muffs?

 

[Westie]

Nope.
If your going to run pink through the muffs you have to remove the t-stat. By the time your get the block drained the t-stat will be closed.

 

[Lazy Daze]

Nope.
If your going to run pink through the muffs you have to remove the t-stat. By the time your get the block drained the t-stat will be closed.

Plus the AF won't be at a high enough temp, either.