Winterize questions

[Dirtymike20]

I've done some research.. but multiple threads on the subject. I live in nebraska and my boat is just under a carport.
After draining the motor.. fill a drum with rv antifreeze and run a hose with muffs till red comes out of the exhaust.. then should I drain the antifreeze? Or leave the engine full.

My engine block drain ports have hoses that lead to a lower hose. Alot of the hoses lead to this plastic dome with a plug. I know it drains most of the water but I'm very certain not all water is leaving the engine.. but main question.. do I leave the AF in the motor? Or should I drain after flush.
Any tips or tricks?
It's a multi port 5.0 merccruiser bravo 3.
Like I said I have a plug at the top by the thermostat I think.. one on the front that most of the hoses run to. And also two on the water pump I believe. Its on the right side of the engine, two plugs vertical of each other 3 inches apart.

 

[achris]

I've done some research.. but multiple threads on the subject. I live in nebraska and my boat is just under a carport.
After draining the motor.. fill a drum with rv antifreeze and run a hose with muffs till red comes out of the exhaust.. then should I drain the antifreeze? Or leave the engine full.

Your choice.

My engine block drain ports have hoses that lead to a lower hose. Alot of the hoses lead to this plastic dome with a plug. I know it drains most of the water but I'm very certain not all water is leaving the engine.. but main question.. do I leave the AF in the motor? Or should I drain after flush.

You need to be SURE all the water was out of the block, heads AND manifolds BEFORE you suck up the AF. Pull the block (and manifold) drains and poke the holes with a small screwdriver or stiff piece of wire, make sure all the water is out... All of it!

Any tips or tricks?
It's a multi port 5.0 merccruiser bravo 3.
Like I said I have a plug at the top by the thermostat I think.. one on the front that most of the hoses run to. And also two on the water pump I believe. Its on the right side of the engine, two plugs vertical of each other 3 inches apart.

You also need to remove the big hose from the water pump and drain that too. Also, don't forget the power steering cooler...

Chris.....

 

[dubs283]

Pull the block (and manifold) drains and poke the holes with a small screwdriver or stiff piece of wire, make sure all the water is out..

Sounds like OP's engine has the single point drain system with plugs on the seawater pump?

If so, OP, the process you describe in your first post will work. Remove single point drain plug ( lower most blue plug in the gray ball housing port side bottom) and both plugs on the sea water pump. You may then reinstall the drain plugs and run the engine while supplying antifreeze to the cooling system and drain everything again. This is the best bet to ensure maximum freeze protection.

FYI some of the early MPI cool fuel (4?) modules did not have drain plugs on the forward bottom face, only cooling supply hoses on the back. I've never seen one freeze damaged when flushed with antifreeze so this route is your best bet

 

[Dirtymike20]

Yes. I have the single port drain system. I was thinking of pulling the hoses off the block and manifolds(both sides) and poking around. Then putting it all back together. Then ill gravity feed AF in and once I see af coming from exhaust I'll still wait for abit while it comes out good. Then drain the system again.. what hoses should I pull for water pump. They are around 1.5" round. Top or bottom hoses. I can also take some pics and post later maybe someone can point them out.

 

[Dirtymike20]