Verifying Proper Cooling System

[Prop Buster]

I downloaded the Service Manual for Marine Engines 305 CID (5.0 L) for which I have to investigate and to learn all about the system.

I find out that the 305 isn't even listed as a Sea Water Cooling Model.
But it's listed as a Closed Cooling Model.

The boat has a Sea Water Cooling System in it.........

I tried to call Mercruiser , spoke to a wondeful lady who knew absolutly nothing, and deflected my queston to Sierra's Customer Service Technical Dept.??

They of course, were too bust to actually answer my call , but I left a message anyway.......

Am I reading Chapter 6 A in the manual right??

Any verification on this question would be appreciated.

Thank You in advance

Prop

 

[Bt Doctur]

Re: Verifying Proper Cooling System

If it has a heat exchanger ,it`s closed cooling.
no heat exchanger, it`s raw water cooled.
both types have a raw water pump to supply the cooling water.

 

[Don S]

Re: Verifying Proper Cooling System

What manual did you download, and what YEAR engine do you have? And are you sure of the engine year (not always the same year as the boat.)

 

[Prop Buster]

Re: Verifying Proper Cooling System

I downloaded the Mercruiser Service Manual Number 17

I am NOT sure of the year of the engine but will VERIFY that when I take a closer look at the engine on Thursday.(by looking at the engine identificationnumbers that I dwnlded )

I assumed that it is a 1995 Maxum...that it must have a 1995 engine in it.

I know that's wrong.......

It has a Sea water cooling system in it ONLY..... NOT a closed system.

The Number 17 Manual Chapter 6A only listed the MCM 350 CID / 5.7 L engine as the only Seawater Cooling Model......I have the 305 5.0 L engine

 

[Don S]

Re: Verifying Proper Cooling System

Going to assume you have either a 95 or 94 engine, doesn't really matter at this point. It is the correct manual.

I find out that the 305 isn't even listed as a Sea Water Cooling Model. But it's listed as a Closed Cooling Model.

Where are you reading this at? As far as I know, there is no lising in the manuals as to which ones have or don't have raw water cooling.

I tried to call Mercruiser , spoke to a wondeful lady who knew absolutly nothing, and deflected my queston to Sierra's Customer Service Technical Dept.??

I'm sorry, but I can't imagine you talking to someone from Mercruiser customer service sending you to an aftermarket parts service.
What phone number did you call for Mercruiser?

Am I reading Chapter 6 A in the manual right??

Any verification on this question would be appreciated.

Not exactly sure what you want to know. A raw water cooled system in Mercruiser terminology is "Standard Cooling"

If you have a raw water cooled 305 with an Alpha drive, see page 6A-20
if you have a Bravo drive, see page see page 6A-22

 

[Prop Buster]

Re: Verifying Proper Cooling System

Don,

Appreciate the help.

Looking at the page that has "Cooling System " Seawater Cooling Models 6 A ( doesn't have a page number)

The very next page after that is the table of contents.
Top line says MCM 350 CID / 5.7 ...............6A-1
Underneath that line is Torque Specifications.

I DID NOT see any other models listed.
So I was wondering if my 305 CID Engine should be a closed system......

The number I called was after I clicked on the top of the page at this website for Mercruiser I/O parts.
The phone number is 800-914-1123.

I'm not pulling your leg but the young lady there said she couldn't help me but the technical service Dept. (I swear she said Sierra) could help me.
I called that number (I don't have it it's on my desk at work) they werre accepting messages only.

Nonetheless, I guess there is a Mercruiser 305 CID engine with sea water only coolant system.But I really don't see it listed as a 305 on page 6a-20. only a MCM 350 CID /5.7 in the table of contents.

I bought the boat used 3 yrs. ago and was wondering if they did something I wasn't aware of until now.


Thanks again

 

[Don S]

Re: Verifying Proper Cooling System

The number I called was after I clicked on the top of the page at this website for Mercruiser I/O parts.
The phone number is 800-914-1123.

No wonder she couldn't help you, you didn't call Mercruiser, you called iboats parts, that is where you can order parts for Mercruiser engines. Nothing to do with Merc technical help, or customer service.

Nonetheless, I guess there is a Mercruiser 305 CID engine with sea water only coolant system.But I really don't see it listed as a 305 on page 6a-20. only a MCM 350 CID /5.7 in the table of contents.

That manual doesn't list them like you think. The manual covers all 305 engines from 93 thru 95, and 350's from 93 to 97.......... all of them, and they don't give individual sections with SN listing. Look at page iii (third page in from the cover) for the list of SN's covered in the manual.

Top line says MCM 350 CID / 5.7 ...............6A-1
Underneath that line is Torque Specifications.

I DID NOT see any other models listed.
So I was wondering if my 305 CID Engine should be a closed system......

Had you been a dealer, you would have received a bulletin to change the wording and add 305 along side the 350 as it was put in section 6B
The cooling system is the same for a 305 as it is for the 350.

 

[Prop Buster]

Re: Verifying Proper Cooling System

Ok Don,

Thanks for the clarification.

Just need to slowly and methodically figure out why this engine continues to plague me season after season with overheating......

I'll get it ........someday

Thanks again

 

[Don S]

Re: Verifying Proper Cooling System

What you need to do, instead of asking all this weird stuff is start a new thread with your engine information, and describe the problem you are having.
I would guess that 99% of all overheat problems that people ask about here are solved once they know what to look for.
Those manuals are not step by step manuals for newbe's, they were designed with a Merc trained tech reading them.