Mercury 3.0 TKS Winterization

[rnorman3]

Hi everyone, I have this motor 3.0L TKS. The "Operation, Maintenance & warranty manual" that came with it says on page 69 of Maintenance to check the Engine coolant and shows like a radiator cap. I thought my engine was entirely cooled by seawater. Can some engines have this feature and others not?

Thanks!

 

[woody66912]

Re: Mercury 3.0 TKS Winterization

Yes they can have a heat exchanger, do you see a tube 2' long and 4" in diamater, if so then you have a closed cooling model. If not then you should have two blue hoses with quick disconnect fittings on the block.

 

[Don S]

Re: Mercury 3.0 TKS Winterization

I moved this over to the Mercruiser section.
You have a Mercruiser by Mercury Marine, Mercury is the outboard division of Mercury Marine.
The TKS is the Turn Key Start system on Mercruiser carbed engines.
Yes, your engine can be raw water cooled or have a closed cooling system. They both use the same owners manual.

 

[rnorman3]

Re: Mercury 3.0 TKS Winterization

Thanks guys, that's great I'm learning a lot here. So I found some more info, I do have the open cooling system only. I'm trying to figure out something though....maybe you can answer. In the picture attached is an open thermostat and a closed from a book I found. I guess when you initially start an empty engine the impeller in the leg fills the block though the port you see via the blue arrows thermostat closed. What's to stop the water from coming back out though the same hole (red arrows on the left)? Is there a check valve there or does the block actually fill from somewhere else?

p.s. I found a smaller hose that branches off the hose that goes to "inlet from stern drive" port in picture and goes to the bottom of the block. This is, I suspect how the engine block is initially filled with water on dry startup, but if that's the case these pictures are not for my engine. I also took the thermostat out and could not see how the water could get from the inlet to the block with the thermostat closed.

Thanks!

 

[Don S]

Re: Mercury 3.0 TKS Winterization

What is the serial number of your engine? Do you have a closed cooling system or raw water cooled?

On a raw water cooled system, if the block is dry when you start the engine, the pump in the drive (raw water pump) feeds water to the thermostat housing which fills the complete cooling system, both block and manifold.

 

[rnorman3]

Re: Mercury 3.0 TKS Winterization

Thanks Don S, my serial is 2A035658 as far as I can tell. But can you tell me what stops the water from going back out of the block though the same hole where it goes in like in the picture? Is there a valve or something there? From the picture there seems to be no difference with the thermostat open or closed, there's still a flow path.

Thanks!

 

[Don S]

Re: Mercury 3.0 TKS Winterization

Thermostat housing is at the top of the engine block, the water can't drain up to get out of the block.