PCM Engine ID + Winterization

[PoisedonsTrident]

Hey guys, not sure if this is in the right sub forum but I wanted to introduce my new boat. It's a 96' Natique with a 5.7 Pro Ski HO. I believe this is a chevy 350 right? Engine Model number PLLPRR12TBI (not getting a whole lot back from Google). This appears to be a more rare engine from what I can tell. It looks like most of the engines in this era of Natique were Ford 351's, right?


Anyways, going through winterization for the first time (this is my first boat). I ran some clean water from a bucket through the engine and and fuel stabilizer. Removed the impeller..

I need to pull the bolt's out of the back of the exhaust headers and drain the water from the plug on the side of the block, correct? I live in Washington state (west side of mountains) so the winters are very temperate. Additionally, I've got the boat in my garage which is insulated. Do I NEED to run antifreeze through the motor? Cap, rotor and plugs were all replaced recently so I'm hesitant to replace them again until maybe next year. What other steps am I missing to winterize? i've watched a bunch of different videos but I can't seem to find any on youtube of this motor. Everyone seems to have the GT-40, etc...

[NautiqueJeff]

Personally, I would just drain it and not worry about the anti-freeze. Pull the two block plugs, the two big plugs on the exhaust risers, the little plug in the transmission cooler, the little plug in the engine circulating pump, and empty the strainer cup.

If the block drains don't start draining a good bit of water after being removed, you may need to run a coat hanger or similar device in and out of the holes a few times to clear built-up scale.

That is a pretty rare engine. Not many pre-Excalibur 350's around. There were a few Apexes, but the 5.7 Pro Ski is quite rare.

You might also check out this thread. The drain points will be very similar.

https://www.planetnautique.com/vb5/f...2012-nautiques

[charlesml3]

And I'm going to go in exactly the opposite direction as Jeff. I'm going to say do NOT pull the brass plugs out and instead, use the "5 gallon bucket" method to displace the water in the block with antifreeze.

Here's why: Most likely, those brass plus have never been removed. The problem here is they tend to seize in the block and when you go to remove them, at least one of them will wring off. Then you're looking and a whole different, difficult, and frustrating problem. I've seen it happen more than once.

For 17 years, I winterized my 99 Air Nautique using the bucket method. It works and doesn't run the risk of breaking off a plug.

-Charles

[NautiqueJeff]

I guess we'll have to agree to disagree. I would not recommend the method Charles uses.

[charlesml3]

I guess we'll have to agree to disagree. I would not recommend the method Charles uses.

And why not? Are you saying it doesn't work? I know for a fact that it does as I've done it and I've watched the service techs from White Lake Marine do it many, many times on engines that had brass plugs. Once PCM went to the blue plugs it's much easier, but that doesn't apply here.

-Charles

[NautiqueJeff]

That is not the method recommended by PCM. After owning over 30 Nautiques over the past 22 years, I have never experienced any issues with the brass plugs at all. Diluting the pink stuff with any remaining water in the system certainly reduces the capacity of the anti-freeze. The pink stuff is not meant to be diluted.

Alas, I am not here to argue with anyone. If you are in a region that never gets truly cold (like we are here in NC), this may work just fine. If your method works for you, great.

There is certainly nothing wrong with doing it the way I (and PCM) recommend though.

[Jonny Quest]

I agree with what Jeff recommends.

1. The "RV" antifreeze is not designed to be diluted and does not mix well
   1. That's why the block needs to be drained before any RV antifreeze is used
   2. Just pouring RV antifreeze into an undrained block is asking for trouble
2. The block and manifold drains should be removed to probe for scale using a wire.
3. Deal with any corrosion in with the drain plugs now vs. later
   1. If any threads look buggered-up, you can "chase the threads" with a tap to clean them up
4. I use a brass reducer bushing on the manifolds with a brass plug
   1. This takes the buggered-up threads out of the equation
5. If you want a quick-and-easy solution for future winterizing, you can install "petcocks" or drainage valves with the removable handle
   1. McMaster Carr has them - part number 4921K2 (see pic below)

+1 on the SBC 350 engine. My buddy has a 1997 SN with that engine. It's a strong runner.

JQ

[scottb7]

I have done both on my G21 and obviously both work. I don't know of any dealer that pulls plugs. And that is here in Minnesota. I used to suck in 6 or more gallons and was sure it was running bright pink coming out...

Is there an issue around the thermostat potentially not being open on this particular engine if you do the suck in rv antifreeze method?

[charlesml3]

Is there an issue around the thermostat potentially not being open on this particular engine if you do the suck in rv antifreeze method?

That's usually the step that gets skipped, or at least not done properly. Part of the "bucket method" of winterizing an inboard engine is "bring the engine up to operating temperature with a fake-a-lake or some other method."

When WLM was winterizing my 1999 Air, they would lower it down on the lift until it was barely floating, start it up and let it run until it reached operating temp. This also served to circulate the sta-bil through the entire fuel system. Anyway, once it was warm, they'd raise it back up and disconnect the raw water hose from the hull fitting and stick it in the bucket. Six gallons of pink antifreeze and they'd shut the engine down as soon as the bucket neared empty. That was about it.