Diagram for coolant system?

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
Messages
40,978
I appreciate all of the info. The boat came to me with the engine already torn down and I saw a huge weld on the inside of the block. I decided to replace it with a 350 vortec engine I had. I never saw the boat engine intact, which has me at a disadvantage. Is there by chance a video somewhere that might help me understand the conversion from auto to marine? Or a book/manual I can order?
Is the motor out of a car, or truck?

If out of a car, you need a marine/RV/truck cam

As indicated, you will need brass core plugs, marine head gaskets, and a marine circulation pump
 

nola mike

Rear Admiral
Joined
Apr 22, 2009
Messages
4,281
motor out of a car, or truck?

If out of a car, you need a marine/RV/truck cam

As indicated, you will need brass core plugs, marine head gaskets, and a marine circulation pump
Are the tstat housings different for fwc/rwc engines? Short of having a HX or a circulator pump in your box o parts it might be tough to tell the difference. Plus it could be a half or full system... Don't know what merc offered then.
 

DiLevan

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May 8, 2022
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I’m not the person to ask, but I know just enough to say, make sure you do this conversion right. Starter and alternator (as well as anything electrical) must be electrically sealed for marine use, otherwise, the possibility exists for a big boom. Seems I have read that the cam may need to be replaced as well. Cams built for auto use are not really the right fit for marine use. Pretty sure there are other differences as well.
Thanks. All good to know!
 

DiLevan

Cadet
Joined
May 8, 2022
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No vid or book. Other then items as Buster mentioned, need a marine head gasket, brass or stainless block core plugs, and marine circulating water pump.
Sure wish there was! I appreciate all of you taking the time to answer. I'm collecting all of this great info. I figured it was gonna be a big job. I just want to get it right. I appreciate any advice. A good manual of a marine engine might help for starters.
 

DiLevan

Cadet
Joined
May 8, 2022
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Are the tstat housings different for fwc/rwc engines? Short of having a HX or a circulator pump in your box o parts it might be tough to tell the difference. Plus it could be a half or full system... Don't know what merc offered then.
It's out of a Chevy truck. I'm at a loss. Can you recommend a water pump?
 

alldodge

Supreme Mariner
Joined
Mar 8, 2009
Messages
37,081
We don't know exactly what you have to work with. Early in the posting you mentioned a 1989 was original by installing a vortex block out of a truck.

Issues are what are you gong to use from old motor? If using the original thermostat housing and exhaust then ok, but might be some issues with things matching up. Not to hard to fix maybe but still what is your plan?

If wanting to update to newer exhaust and thermostat housing for a vortex this is ok, just need to know.

How about posting pics of what you want to use from old motor?
 

DiLevan

Cadet
Joined
May 8, 2022
Messages
11
I have the old engine, just in pieces. I intended to use the block from the vortec and the external parts from the original Mercruiser, (I think it is). I will get some pics to post.
 
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