3.0L Merc Winterizing Question

[thompsdw]

I think I only have one drain plug on my 99 3.0L Merc engine. Is that correct? I could only find one. I check the exhaust riser and found a plug there, but there was no water at all. I guess the single block plug drains everything on this engine????

 

[cobra 3.0]

Re: 3.0L Merc Winterizing Question

Not sure about the merc 3.0. My Cobra 3.0 has one on the block and on the exhaust riser. I had tons of water in both. Try using a stiff wire into the hole...maybe it's blocked. You may have to remove the drain with a key to see if all is clear. I'd be concerned if no water came out.

 

[merc 140 pontoon]

Re: 3.0L Merc Winterizing Question

txbb - That doesn't sound right to me. My 140 is much older (1974). All drains are on the port side of the engine. There is one petcock on the side of the engine block, below the manifold. There is one plug on the bottom of the manifold. And there is one plug on the side of the riser. I always get a lot of water out of the engine petcock and the manifold drain. I generally get nothing out of the riser drain, even after clearing it out very thoroughly with a wire or small screwdriver. It sounds to me like you have missed the plug on the bottom of the manifold.<br /><br />Steve

 

[Goeb1133]

Re: 3.0L Merc Winterizing Question

Two drains. One block plug and one exhaust manifold plug. both on the port side.

 

[merc 140 pontoon]

Re: 3.0L Merc Winterizing Question

I think Goeb is right. I checked the diagrams for both years, and it looks like they've eliminated the plug in the new exhaust elbow design. I'm surprised you didn't get water out of the manifold plug. I'd try probing that hole with some wire, as cobra said.<br /><br />Steve

 

[paragod]

Re: 3.0L Merc Winterizing Question

I pump anti freeze in my engine is the wrong for the winter? I have a 5 gal bottle with a hose vale and some hose makee 50/50 mix put it abovee the out drive and let it suck it in with gravity assist until it somes out the drive and bypass holes on the transom

 

[merc 140 pontoon]

Re: 3.0L Merc Winterizing Question

Yes, it is best to winterize with antifreeze. Some people use the RV stuff, but that doesn't contain anticorrosion agents. Some people use regular green auto antifreeze, but that is extremely bad for the environment. You should use propylene glycol with anticorrosion additives. I tried the "gravity assist" method with a bucket and hose exactly once, and didn't like risking the I/O pump impeller in my Merc 140. So I bought a winterizer kit that has a tank and a valve. You need to get the engine good and warm to be sure the thermostat is open, or do like I do and pull the t-stat for this step. Many people use the old method of pouring the antifreeze into the hoses near the t-stat housing, with the drains cracked open to confirm they are filling the block and manifold. Some people drain the drain plugs after putting in the antifreeze, but most experts I've talked to say to leave it all in there to protect the internal surfaces against corrosion. Of course, before all of this you need to heat up the engine, change the oil and filter, run it again to check for leaks and run the fresh oil through the engine. When doing the antifreeze through the pump routine, you want to fog the engine through the carb the whole time, then heavily just before the antifreeze is gone, to choke off the engine. Then I like to pull each plug and squirt a little Marvel Mystery Oil in each cylinder. I also spray all the metal components down with a corrosion protector--I'm now using Corrosion Block spray. These procedures are discussed in detail at many sites online--my instructions herein are just babbling--get a manual or find some detailed instructions you trust.