Cooling system diagram

[mmuutts]

small block GM 305/350 family 220-260hp, fresh water cooled, with the 2 barrel carb I`d say 220hp but not postive.

Does any one have a diagram of the cooling system? I am told I have a heat exchanger.

Would like to know how it works and flows ect...

 

[Bondo]

Re: Cooling system diagram

small block GM 305/350 family 220-260hp, fresh water cooled, with the 2 barrel carb I`d say 220hp but not postive.

Does any one have a diagram of the cooling system? I am told I have a heat exchanger.

Would like to know how it works and flows ect...

Ayuh,... Who's drive,..?? What drive,..??

How about a Serial #,..??

 

[mmuutts]

Re: Cooling system diagram

Sorry...still getting used to what info I have to put down....SEI 106 outdrive....I still have not found a serial number...

 

[Bondo]

Re: Cooling system diagram

Sorry...still getting used to what info I have to put down....SEI 106 outdrive....I still have not found a serial number...

Well,... I guess that means it's a Mercruiser motor,..??
About what Vintage,..??
Got any Pictures,..??

 

[mmuutts]

Re: Cooling system diagram

To funny...yes mercruiser 305 5.0 litre engine......1984 SR Cuddy fisherman....I just want to understand how the cooling system works. Here are some pics of the engine. This is my first inboard.....Thanks.

.......

 

[Don S]

Re: Cooling system diagram

The engine is much newer than the boat, and you have an aftermarket heat exchanger. Can you post a picture that shows the thermostat housing? That will help ID a suitable cooling system diagram.
It appears that you have a FULL cooling system, the manifolds are cooled by antifreeze and only the risers cooled by raw water.
You also have an engine mounted sea water pump. (Lower left in your above picture)
What outdrive do you have?

 

[mmuutts]

Re: Cooling system diagram

Wow...sounds pretty cool....I take it thats a good thing for salt water..Re;? SEI 106 outdrive....
Re;Thermostat housing..Where would that be located?
What is the engine mounted sea water pump for?

Thanks Don!

 

[Don S]

Re: Cooling system diagram

Here is a diagram of a closed cooling system, not exactly what you have, but you will see what does what and how the flow goes between the raw water (aka sea water) and the coolant sides. The sea water pump is what cools the heat exchanger (much like the air on the radiator of your car) and the hot exhaust gasses coming out of the elbows so it does not burn up the hoses in the sytem, and keeps the inside of that closed engine compartment from getting really hot from glowing red exhaust sytems.

 

[mmuutts]

Re: Cooling system diagram

OK...I get it..thanks a lot.... So... I have a sea water pump...which would mean its sucking sea water from a thruhaul..but also the outdrive has its own pump/impeller. Thats where I am confused...is with the ear muffs on that is for the outdrive..not the engine..right? So I need to find where the sea water intake is for the engine...right?
I want to run the engine....do I need to have a second water hose hooked up somewhere else?

Sorry for the Dummy ?'s and thanks again....

 

[mmuutts]

Re: Cooling system diagram

Hi Don S,

Here is another picture...I am not seeing a sea water pump. It looks like to me there is no fresh water/sea water getting to the engine? Does the fresh water from the oudrive impeller pump the water to the engine?

 

[Don S]

Re: Cooling system diagram

What I thought was your raw water pump in your original picture, now shows as an idler for the belt.
Your raw water pump is in your outdrive.
So, with that information and your wanting all this cooling system information, can I assume your engine is overheating at higher rpm? Yet cools fine at lower rpm and speeds?

 

[mmuutts]

Re: Cooling system diagram

Thanks again Don...

No....I do not know if its overheating...I just got the boat...long story....and am going through it..wanting to make sure everything is ok before I take her out....or for that matter run the engine, to tune it up etc...And I like to understand everything in case something breaks etc...The boat was sitting in the water for a few months without suppervision. This is my first outdrive type boat. I have it at home on the trailer now.


If the outdrive provides the fresh water to the engine where are the hoses at? do they enter from the rear of the engine block or go thru the exhaust some how?

Thanks for all your help