Winterizing 8.1s and the AC on a 2004 340

mrsrobinson

Well-Known Member
Mar 9, 2006
7,704
Virginia
Boat Info
2001 380DA
Engines
Caterpillar 3126
If all goes well with sea trial, survey and engine compression checks I will be the proud owner of a 2004 340 by end of next week. After boating it home I will need to winterize soon. I have winterized all of my previous boats myself, inboards and outdrives.

Looking at these 8.1s I see an air pump of sorts attached to the raw water heat exchanger, looks like the kind of pump I used as a kid to pump up my basketball. What is that for?

My plan is to:

- warm up the engines (is this necessary since I do not have to open the thermostats?)
- shut down the engines
- close engine sea cocks
- open up all raw water drain plugs (can someone tell me where they all are?)
- drain raw water
- remove raw water hose at seacock
- insert hose into bucket of pink RV antifreeze (how much antifreeze per engine?)
- start engines, shut off engine when I see pink coming out of the exhaust

Did I miss anything?

Also, how do I pump antifreeze thru the AC line? In the past I have used a pump on a drill to push antifreeze thru the line from the exterior hull fitting, where the AC water exists, until the seacock fills up. The boat will be in the water so I will not be able to do that, unless I get lucky enough to have a floating dock with that side of the hull on the dock.

Thanks
 
Close the sea cock and pour antifreeze into the strainer as the unit is running. A gallon should be enough, maybe 2 for insurance.
 
Close the sea cock and pour antifreeze into the strainer as the unit is running. A gallon should be enough, maybe 2 for insurance.
Thanks, I missed that step but was planning to do it. So 2 gallons tops for each engine?
 
Thanks, I missed that step but was planning to do it. So 2 gallons tops for each engine?

I use the SeaFush and their snorkel attachment as it makes it a little easier. It is also easier with two people - one down with the engines and one at the helm.

I first warm up the engines with fresh water going into the strainer from hose running the engines on the premix cocktail. I hook up just before the fuel filter.

Then I then change the oil while the engine is warm.

Then we put the Seaflush into the strainer and the snorkel into a 5gal bucket of Pink AF. Open the drain on the muffler. When water stops draining start the engine and wait for the pink to flow out. Shut down close the drain and your done. On the 8.1s your looking at 4-5gal per engine.

-Kevin
 
I use the SeaFush and their snorkel attachment as it makes it a little easier. It is also easier with two people - one down with the engines and one at the helm.

I first warm up the engines with fresh water going into the strainer from hose running the engines on the premix cocktail. I hook up just before the fuel filter.

Then I then change the oil while the engine is warm.

Then we put the Seaflush into the strainer and the snorkel into a 5gal bucket of Pink AF. Open the drain on the muffler. When water stops draining start the engine and wait for the pink to flow out. Shut down close the drain and your done. On the 8.1s your looking at 4-5gal per engine.

-Kevin
I researched SeaFlush last year and wasn't sure it was the real deal. Glad to hear it works well, I may try it out.
 
1+ on SeaFlush. Used it last 2 years. Works great for Engines, Genny and AC.
AC should take about 2 gallons and Engines 4-5 gallons each as mentioned. I also get engines to operating temp, change oil/filter, run 5-10 gal of fresh water through and then 5 gallons of antifreeze for engines. Do same with smaller amounts with Genny. For fresh water system, make bypass for hot water heater, run water tank empty, add 3 gallons pink antifreeze to water tank and run each faucet and head til pink. Just drain hot water heater and remove bypass and run some antifreeze into it as well. For holding tank, make sure pumped out and add 1 gallon of pink through toilet. Also - don,t for =get the sump pump for the shower / AC drain. I pour pink antifreeze into AC pan and wait for it to show up in sump and then fill so sump runs for at least 3 cycles.
 
I use the SeaFush and their snorkel attachment as it makes it a little easier. It is also easier with two people - one down with the engines and one at the helm.

I first warm up the engines with fresh water going into the strainer from hose running the engines on the premix cocktail. I hook up just before the fuel filter.

Then I then change the oil while the engine is warm.

Then we put the Seaflush into the strainer and the snorkel into a 5gal bucket of Pink AF. Open the drain on the muffler. When water stops draining start the engine and wait for the pink to flow out. Shut down close the drain and your done. On the 8.1s your looking at 4-5gal per engine.

-Kevin
So Kevin,
1) Do you drain the motors’ blue plugs (obviously not the block where the antifreeze is) or use the air pump before adding antifreeze to the strainers? I have the same mufflers and see the drain plug there, was there any difficulty removing that plug? Is there a rubber washer on it and do you replace that?
2) What do you use for the temporary fuel tank? An outboard tank? Do you need the bulb or do the pumps create enough vacuum to draw the gas out?

Thanks
 
2) What do you use for the temporary fuel tank? An outboard tank? Do you need the bulb or do the pumps create enough vacuum to draw the gas out?

Another option (besides the portable OB tank) is to add the combo of gas + 2-stroke oil + stabilizer to a new fuel/water separator, since you are changing that anway, and run the engine briefly on that. I don't have the amounts handy but I could get them for you.
 
Another option (besides the portable OB tank) is to add the combo of gas + 2-stroke oil + stabilizer to a new fuel/water separator, since you are changing that anway, and run the engine briefly on that. I don't have the amounts handy but I could get them for you.
Our boats don’t have a spin on water separator - which is why Kevin and others use a separate fuel tank and connect to our cool fuel inlet gas line.
 
Last edited:
So Kevin,
1) Do you drain the motors’ blue plugs (obviously not the block where the antifreeze is) or use the air pump before adding antifreeze to the strainers? I have the same mufflers and see the drain plug there, was there any difficulty removing that plug? Is there a rubber washer on it and do you replace that?

Our 8.1s have coolant and are protected from freezing. Its the raw water cooling for the exhaust side that we need to worry about only which also includes the other coolers inline. Generally I will use the hand pump to open the drains first and let the water come out. I will then also drain the mufflers but leave the drain plug out. Using the Seaflush and snorkel I hook it up to a strainer and fill a 5 gallon bucket with Pink AF. Then start the engine and let is suck the AF through the system. This is best done with two people since one will be down with the engines and the other up at the helm. Once the muffler drain is running solid pink your done - AF has been pushed through the system. 5 Gallons will go through the system real quick.

2) What do you use for the temporary fuel tank? An outboard tank? Do you need the bulb or do the pumps create enough vacuum to draw the gas out?
Thanks

I have a small outboard tank with a hose with a flare fitting on it. While I do have the spin-on fuel/water separator I still use the tank. I just undo the fuel line going into the inlet port and attach it there. Then with the tank attached to the port I run it through for a few minutes. This is generally done before doing an oil change to warm up then engine and before the AF is introduces. Then disconnected and moved to the next engine and the process repeated.

-Kevin
 
Our boats don’t have a spin on water separator - which is why Kevin and others use a separate fuel tank and connect to our cool fuel inlet gas line.

Actually mine does have a spin on filter. The Cool Fuel 3 system was introduced in 2005 models. I have a 2004 model.

-Kevin
 
Actually mine does have a spin on filter. The Cool Fuel 3 system was introduced in 2005 models. I have a 2004 model.

-Kevin
Thanks for the info - and I stand corrected on the spin on (sorry Phil)

I was winterizing everything else last weekend and looked at how I have to access the blue plugs after using the hand pump.
I will take my advil before starting this contortionist activity :)
 
Thanks for the info - and I stand corrected on the spin on (sorry Phil)

I was winterizing everything else last weekend and looked at how I have to access the blue plugs after using the hand pump.
I will take my advil before starting this contortionist activity :)

Which blue plugs are you referring to? If you are referring to the ones on the raw water pump then don't worry about them as plenty of AF will be pumped through. If you close the seacock and pump AF from the strainer through everything will be protected on the raw water side.

-Kevin
 
I drain my engine mufflers first then put plug back in. I then run in 2 gallons of pink by pouring it into the strainer and cranking the engine with the wire off the coil so the engine will not start. Block the line to the hull valve. No pink comes out the exhaust.
 
Which blue plugs are you referring to? If you are referring to the ones on the raw water pump then don't worry about them as plenty of AF will be pumped through. If you close the seacock and pump AF from the strainer through everything will be protected on the raw water side.

-Kevin
Yes I was referring to sea water side. That’s is what I was asking. I wondered if you were in fact using the air pump and then after running af, calling it a day, or did you take the time to drain everything on the seawater side before running af.

Thanks for the reply.

I did purchase the groco strainer caps and made a bucket with a manual valve to a clear hose to connect to the groco. I will have my anti freeze in the bucket gravity fed to the strainer so when I start engine I’ll open the valve and wait for the af to come out of the plug.

I used this already for the ac and generator.

Also - “ I have the same mufflers and see the drain plug there, was there any difficulty removing that plug? Is there a rubber washer on it and do you replace that?”
 
I finally got to winterize engines yesterday. I had already changed oil and transmission fluid last week.

As mentioned earlier I have the groco caps and made a bucket with a valve. I connected a clear hose from bucket to cap and with the valve off filled the bucket. After cleaning the strainer and filling it again, my helper started the engine and I opened the valve and fresh water flushed until I reached operating temp. I shut it down and and vacuumed the strainer out and cycled the seacock. I used the air pump as Kevin suggested to drain the water out and opened the muffler drain plug and found them to be loose and need new rubber gaskets. Once all drained out, reset the pump unit, primed the strainer with anti freeze (I used the purple for added protection) and ran it until purple came out the muffler drain plug. Since I had purchased a case for each motor I just ran all six gallons and left the drain plug open even after I stopped the motor. I checked what came out in a cup while running to verify it was all purple.

Thanks to all who responded as my confidence was high after reading all of this.

Also - I did not run the fogging tank this year as I used stabil on my last runs and am having the fuel injectors and pumps replaced over the winter at this marina. I am prepping that tank to use next year.
 

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