Weed Filter Removal

[fishfoxey]

Hi If I want to remove the weed filter to drop antifreeze in for winter, I obviously shut the sea cock, but do I then need to run or turn the engine over to empty the pipes or can I just unscrew the top and away we go? Also once off do I just pour antifreeze in until it tops out then run for a few seconds until it comes out exhaust,? Is there a risk of damaging the engine if no water is in there? Thx

[OldBerkshireBoy]

Antifreeze stays in the cooling system, what engine do you have?

[fishfoxey]

Mermaid

[oldgregg]

So yeah, antifreeze doesn't go on the raw water side of the heat exchanger.

The river water that comes in (and exits with the exhaust) is used to cool the closed loop on the engine, and it's that you'd add antifreeze to.

[fishfoxey]

I Thought I read somewhere about running antifreeze through the raw water  to protect it during winter

[Cheesey69]

Only if you have a raw water cooled engine where there is no heat exchanger. 
I never drain the raw water because even if it does freeze it has room to expand but I may be wrong on this. 
I close the through hull as a matter of course anyway and if I’m laying up for winter I remove the impeller because you will damage it if it don’t move over winter 

[Oddfellow]

1 hour ago, Cheesey69 said:

Only if you have a raw water cooled engine where there is no heat exchanger. 
I never drain the raw water because even if it does freeze it has room to expand but I may be wrong on this. 
I close the through hull as a matter of course anyway and if I’m laying up for winter I remove the impeller because you will damage it if it don’t move over winter 

You are wrong. Very wrong. A deep winter will

1) Potentially blow your raw water intake pipes and unions apart
2) Potentially rupture your raw water pump
3) Rupture your heat exchanger
4) Potentially rupture your seacock and weed filter - possibly sinking your boat
5) Potentially rupture your waterlock
 

There's a lot of potential for complete disaster by not putting antifreeze through your raw water system as part of standard winterisation. 

Most systems will take at 5-7litres of antifreeze before you'll see it coming out of the exhaust. 

Your raw water pump will not push air. If you turn the seacock off and run the engine for 20 seconds until water stops coming out of the exhaust, that HAS NOT evacuated the system of water as the pump is not pushing air through do do this, it will only push liquid. 

You should also put antifreeze though toilet flus water intakes and it's good practice to do the same tyo shower trays and pumps and even sinks, especially if there is a sink trap or high spot on the fall of the exit hose. Basically, anything that has water runing though should be protected. Drinking water circuits can have a "safe" product run though them or empty the tanks, disconnect the pump (and run it until the water stops spurting out), ideally blow compressed air though the circuit to evacuate water through all the taps and drain the calorifier too.  

 

 

[fishfoxey]

Thats what I thought I had read. Hence going back to my original question once I turn off seacocks do I then run the engine until no water comes out of exhaust ( is there danger of damaging the engine during this short period of no water?). Then take off lids to weed filters (which hopefully means water upstream in the engine doesn't flood out) . Then pour antifreeze down the weed filters, refit lids then run for short time until antifreeze comes out of exhaust , then shut down and everything is hunky dory. 

[Oddfellow]

2 minutes ago, fishfoxey said:

Thats what I thought I had read. Hence going back to my original question once I turn off seacocks do I then run the engine until no water comes out of exhaust ( is there danger of damaging the engine during this short period of no water?). Then take off lids to weed filters (which hopefully means water upstream in the engine doesn't flood out) . Then pour antifreeze down the weed filters, refit lids then run for short time until antifreeze comes out of exhaust , then shut down and everything is hunky dory. 

There is no point in running the engine with the seacocks off as the pump will not move anything other than liquid; it cannot evacuate the water from the engine. Also the pump will not allow any water that has passed it to flow back if you disconnect any hose before the pump - it acts as a one-way valve. That's addressing your point about water upstream flooding back. 

You have to pour 5-7 litres through the weed filter with the engine running and have someone watch the exhaust for the antifreeze. Some small engine circuits may need less than 5 litres, but not much. 

[fishfoxey]

Ah I think see so with the sea cocks closed and weed filter lid off i can just pour the antifreeze down it until it comes out of exhaust the refit filter and lid and were done? Sorry if the questions seem dumb but if you google it you get all manner of answers so as a rookie boat owner you don't know what to do. Thanks for your help much appreciated 

[StillCruising]

I have a large raw water filter mounted on the bulkhead. With the engine off I close the seacock and undo the lid of the filter. Start the engine and pour the antifreeze into the filter where the pump will push it around the engine until it appears at the exhaust then turn of the engine and put the lid back on the filter. I always pump all the water out of the fresh water system, leave all the taps open and take the pipes off the pump. 

[Cheesey69]

Got it. 
Never did this when I was in the seas but then never experienced iced conditions 

so what’s best if you want to cruise in winter?

 

[Regulo]

Do you have shore power? I keep two tube heaters in the engine bay, linked to a frost stat. Remove the weed filter cap, shut the inlet seacock, run the engine until there's no water from the exhaust, and that's it. If you want to cruise, put the top back on the filter, open the seacock and off you go. Done it like this for 20 years, and never a problem.

[fishfoxey]

Yes got shore power so got myself  couple of tube heaters for the engine, and plan was to then put antifreeze in the raw water so if I want to use it in the winter only have to open sea cocks and then away. Everyone has said one of the best times to go out is over the quieter winter months

[Smoggy]

Don't use regular antifreeze, there is a non toxic version (I use freezeban) and it's cheaper.

Big freezes are rare these days so I pump a couple of litres through each engine, I don't even look at the exhaust to see it come out (I doubt I'd notice), survived the beast from the east so it does me, my volvos take a fair drop too.

[Oddfellow]

10 hours ago, Regulo said:

Do you have shore power? I keep two tube heaters in the engine bay, linked to a frost stat. Remove the weed filter cap, shut the inlet seacock, run the engine until there's no water from the exhaust, and that's it. If you want to cruise, put the top back on the filter, open the seacock and off you go. Done it like this for 20 years, and never a problem.

As I have said, there is no point in running the engine with the seacock off until you get no water from the exhaust. The raw water pump will only pump liquid. It will not push air through the cooling system of your engine and expel the water. What it will do is run the impeller dry and the impellor needs water as a lubricant and coolant. 

[fishfoxey]

In which case how do i get the antifreeze into the weed filter if I don't turn off the seacocks and run engine to clear the pipes on weed filter side of impeller. Could I use a wet/dry vac to suck the water out from that side so I can get the antifreeze started?

[Cheesey69]

I think you just open the weed filter close the cocks start the engine. 
as the water level drops in the filter keep pouring anti freeze as the level drops until it comes out of exhaust. 
stop engine, fill filter with anti freeze with the hope that the anti freeze will disperse down from filter to stop cocks. Lid on. 

[NeilB]

Start the engine and let it run at tick over.  Have a watering can of anti freeze mix at the ready.  Turn sea cocks off and slowly pour the antifreeze mix into the filter, you can speed up or slow down depending how fast the mixture is sucked through.  You’ll probably need the whole can but keep going until the mix is flowing out of the exhaust.  If you  have two filters you can pour some mix down both.

Turn off the engine and make sure there is a clear note at the helm that the seacocks are closed.

 

[MauriceMynah]

Is there not a way to just drain the raw water system? I had been lead to believe that taking out the impeller and leaving the cover off did the trick.

[JanetAnne]

Many heat exchanges have a drain off plug underneath somewhere as will the engine block, however,  leaving these components empty can encourage surface corrosion leading to other problems.  Antifreeze contains corrosion inhibitors which protects your metal chambers etc.

By the way, should your exhaust manage to freeze and split during a cold snap you may well not notice until you are away up the river and the floorboards start to float!

 

[annv]

Hi As Andy said you turn off the raw water sea cock remove the top cover remove the filter clean then with 1/2 gallon or so  of 20/25% antifreeze mixture start up engine on TICK OVER at the same time tipping in the antifreeze when all has disappeared  stop engine replace filter and cap leave raw water valve in off position then put a note on helm to remind you to turn on valve when next you start the engine in new year, the cooling system of the engine should have a 5o% mixture kept in the engine all the year round, changing it every few years.  you should also flush the toilet and shower pump as well with a antifreeze mixture it's all very well leaving heaters on during winter but if they trip out due to flooding!!! . the hot and cold system should be drained as well leaving all taps in the open position,   on my presant boat i use the shower pump to evacuate the pipes by turning ball valves on on each run this saves having to remove pipes from fittings with the possibility of damage,  also this makes it easy to do again if i use it during winter, yes pipes won't freeze if there is only a sharp frost for one day but a prolonged period will freeze and cause damage, prevention is better than cure. This should all be done on a cold engine after you have changed the oil and filter.  John

[fishfoxey]

Thanks everyone I think I have the way forward now

[Regulo]

On 03/10/2020 at 07:59, FreedomBoatingHols said:

The raw water pump will only pump liquid.

So how do they self-prime?

[Oddfellow]

23 hours ago, MauriceMynah said:

Is there not a way to just drain the raw water system? I had been lead to believe that taking out the impeller and leaving the cover off did the trick.

There is, but this is a lot of work and actually risky with an older engine. The drain points are often seized through lack of use and maintenance and/or corroded beyond service. You need to remove the faceplate of the pump (or at least loosen to allow the water to drain and any water remaining in the water lock or other areas that you can't get to remain at risk of freezing. 

it's so simple and quick to just fill the engine with antfreeze.

21 minutes ago, Regulo said:

So how do they self-prime?

They can pull liquid though a closed circuit. They cannot push air. That's why if you have an air leak on the draw side of the pump they will fail.