Bravo Sea Pump Freeze Protection

[Merc4ever]

Do I need to remove the hoses from my Mercruiser Bravo 1 sea pump to drain the water for winter storage? I followed the owners manual removed all the blue plugs... But it looks like water could still be trapped in the pump itself even though I cranked it for a second like it said.

Just seems like the safe thing to do would be to pop the hoses off to make sure it's clear of water. But it doesn't tell you to do that. Would it be overkill? Or is it normal procedure for the seasoned Bravo winterizing veterens?

 

[Pete104]

Re: Bravo Sea Pump Freeze Protection

Depends. If the hoses are accessable, pull them & shake them out.

If they are a ***** to get at, run anti-freeze through them.
A flushing device, piece of garden hose & a funnel. Ya get it? Lot a messing around but you know the water is gone! Or just run anti-freeze thru the engine, done!

 

[tpenfield]

Re: Bravo Sea Pump Freeze Protection

If you do the 'draining' thing for winterization, then , yes it makes sense to drain the water from everywhere (every-where). Removing the hoses from the sea water pump will also drain the water from the oil cooler. there is also the re-circulating pump on the engine, which can hold water to some extent in the lower hose area. In total there are about 7 places where you could/should drain.

An alternative would be to run anti-freeze through the engine (after warm-up) and then just drain the block and exhaust manifolds. The remaining areas previously mentioned will have anti-freeze in them to avoid any problems over the winter. The block and the exhaust manifolds typically have 'mixing' issues with the anti-freeze approach, so that the concentration of anti-freeze is unknown, thus favoring the draining approach.

I favor doing the 'hybrid' approach of running anti-freeze, then draining the block and manifolds, because there is less to disconnect, and you avoid the issues of improper re-connection next spring. (been there, done that)

 

[Merc4ever]

Re: Bravo Sea Pump Freeze Protection

I drained the block, exhaust manifolds, fuel cooler, and circulating pump hose drain. * I removed and filled the big hose on the thermostat housing until it came running out the thermostat. That indicates that it's full, then I filled the 2 exhaust manifold hoses off the thermostat until it ran out the back indicating it is full. I will now remove both hoses from the sea pump (Bravo models only) and see what I get.

I'll let you all know if anything is left in there that would damage the pump housing later today so we all will know for sure if it needs to be done.

* When I say filled I used 50/50 antifreeze/distilled water

 

[Merc4ever]

Re: Bravo Sea Pump Freeze Protection

There's NO QUESTION ABOUT IT, REMOVE BOTH HOSES! Both of them were full of clear water after I filled the block with antifreeze. I thought a little antifreeze would of ran back from the thermostat but there was no green whatsoever. It would of certainly cracked my sea pump this winter.

 

[TilliamWe]

Re: Bravo Sea Pump Freeze Protection

I always ran antifreeze through the hoseat the thermostat housing that came up from the sea water pump. When the antifreeze ran out the outdrive, I knew everything got flushed. Much easier than removing and reattaching the two hoses from the (hard to reach) sea water pump. Glad your way worked for you, though.

 

[Merc4ever]

Re: Bravo Sea Pump Freeze Protection

I always ran antifreeze through the hoseat the thermostat housing that came up from the sea water pump. When the antifreeze ran out the outdrive, I knew everything got flushed. Much easier than removing and reattaching the two hoses from the (hard to reach) sea water pump. Glad your way worked for you, though.

I followed the Mercury owners manual and almost missed my water pump. It doesn't tell you to dump antifreeze in that hose. My hose goes down the port side to a fuel cooler then up and over the rear of the engine then down the starboard side to the pump. Maybe if I pulled that line like you say it would get enough head pressure to go up, over, and around to flush out to the pump. I'm not sure if it could reverse push through the pump to the intake side without the pump turning, but if antifreeze came out your outdrive it must. Thanks, it's definitely worth a try next year and like you said it would be much easier. Especially the yoga maneuvers necessary to reach the sea water pump.

 

[Merc4ever]

Re: Bravo Sea Pump Freeze Protection

For the sake of experimenting, and this thread, today I put the two hoses back on the sea pump and poured antifreeze in from the thermostat hose end. It seems to fill up and stop when it hits the pump. I didn't hear any come out of the outdrive. Maybe it was dripping through slow but I didn't see it. To me this seems like the intake side would not be purged of water and it would be vulnerable to freezing.

 

[TilliamWe]

Re: Bravo Sea Pump Freeze Protection

I never had that problem. The housing is not perfectly round and the vanes of the pump usually don't cover both holes at the same time.

 

[Merc4ever]

Re: Bravo Sea Pump Freeze Protection

I never had that problem. The housing is not perfectly round and the vanes of the pump usually don't cover both holes at the same time.

Maybe it's the way my hoses are routed that stops it from coming out. It has to go down to the fuel cooler then back up and around the top rear of the engine, then down to the pump and back up again to get to the drive where it normally comes in.