Mercruiser 165 with Alpha One Coolant flush and Recovery tank help

[H@ystack]

Ok, first, I'm stupid. Let's just get that out of the way. I made a mistake here, let's not rehash that fact right now.

At some point, while working on my boat, I lost the coolant recovery cap. Apparently, this is more important than I thought, now that I have learned about this system.

After getting excited about getting my boat back this week, I forgot to grab a new cap, or try to find the old one in the bilge.

This weekend, I ran my boat. We ran pretty hard for awhile and didn't overheat a bit. We then went out in to Lake Okeechobee and it was a bit bouncy. We think we started bouncing out some of the coolant, which create a cycle of hot engine to boiling over coolant back to hotter engine and more boiling coolant.

I smelled it right away, saw some smoke, although we think it was steam from the water hitting the engine. I killed the engine and we drifted in the river a bit. The gauge dropped below 180 really quick. I planned on sitting for quite a while, but we drifted into some swampy stuffso I started the boat again to get to the ramp 500 yards away. It started fine. We went slow and steady and kept an eye on the gauge. We threw a little bottled water in the reservoir to be safe.

Eased in to the ramp. Sat there with it off while waiting for the trailer. Started immediately to get me up the trailer.

First, I'd like to flush the cooling system, obviously. Get that water out of there and get the proper fluids in there. Can someone give me some assistance on understanding how to do that. I've only done this to older trucks, not a boat.

Second, I'm going to take it to have it checked out. Make sure I didn't melt something, but I think I'm ok. What all should I be looking out for as far as damage is concerned.

Third, is my theory on how important this cap is, correct? If not, I may have another problem. Although, my water pump is running perfect with no problems. I never ran hot until I lost the cap.

Fourth, I need to find a new recovery tank anyway. I see this one is cracked. Is a compatible tank from a car parts store sufficient? Or should I go Marine only? I'm not sure where to find one. I keep getting "ebay hits" when I search in google.

 

[stonyloam]

OK, we are talking about the radiator type cap right? There is a drain plug on the port side of the engine, but you can also drain the antifreeze by removing the forward plug on the underside of the exchanger. You might be able to get a hose and a funnel under it to drain through the hull drain into a bucket so you don't have toxic antifreeze all over the place. Then run your flush and refill.
If your impeller is in good shape it should have provided cooling water to the exhaust, so you should be OK there.
Yes the cap is important to keep the coolant in.
Any coolant recovery tank should be OK. Place it in about the same place as yours. Make sure the hose going to the bottom of the tank has no leaks, and fill the tank to the " cold" line with antifreeze. Check the tank after running and refill if necessary. Check the tank every time as part of your "pre-start routine".

 

[H@ystack]

Thank you Terry. I wasn't sure if an additional kit was needed for an engine flush on this engine. Since it's basically just a GMC, I didn't really think so.

Luckily, I live in Florida where the guys at auto parts stores are boaters as well, so they do a good job of finding parts that work. Apparently, a lot of Chevy Nova parts fit my engine. I'm convinced the word "Marine" just means "add $30 to the price"

 

[stonyloam]

Actually the 470 (it is the 4 cyl engine right) is based on the Ford 460 engine. There are two different "165" engines, one is a 4 cyl (470) and the other is a 6 cyl Chevy engine. Just making sure we are on the same page here LOL. As far as the marine parts, all of the fuel and electrical parts must be marine rated for safety reasons. Includes carb, fuel pump, alternator and starter.