overheating-water pump and impeller?

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Dan Crenshaw

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Joined
Jun 23, 2008
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26
1983 Chris Craft w/mercruiser 350 V-8 260 hp. The water pump has gone out. I am replacing it, the thermostat and whatever else needs to be replaced.
My questions:
1. Does my engine also have an impeller that needs to be replaced?
2. Can I buy the water pump at NAPA or should i buy one from a marine shop? NAPA said they have a marine section and say it is the correct one and can order it.
3. I have seen 2 versions of my engine- 5.7L 260 hp and 5.7L 260 hp MIE. How do I know which engine I have and what is the difference? I assume my engine is original to the boat. It sure looks like it.

I have looked at diagrams and cannot see on my engine where I have a thing that looks like the diagram showing where the impeller is.
I go the diagram online at www.marinepartsexpress.com
Any help is appreciated.
 
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dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,332
Re: overheating-water pump and impeller?

1. the engine mounted circulating pumps rarely fail, it is usually the seals that go - if its not leaking don't worry about it

2. buy a replacement water oump assy kit AND base assy from a mercruiser dealer - you will be happy you did, be sure to give them as much info as possible about your drive; like serial number, year, what it looks like, etc...

3. the MIE engine is mercruiser inboard engine, your model should be the MCM dseignation - mercruiser marine (sterndrive)

here is a link to download the manual that has step by step instructions to install your water pump assy:

http://www.4shared.com/document/zz_5pj9o/Service_Manual_06.html
 
Fireman431

Fireman431

Rear Admiral
Joined
Sep 17, 2007
Messages
4,292
Re: overheating-water pump and impeller?

The engine has a front mounted water pump like a car engine would. There is also a thermostat as in a car. These work the same way, circulating fresh water (if a closed system) thru the engine and then thr\u a heat exchanger, which is cooled by raw water coming in from the lake/river. An auto version would work, but you're asking for another replacement soon. Go with the marine version due to the brass/nickel/stainless steel used in the internals

There is a impeller housed in the lower unit of you outdrive (unless it is a straight inboard--no lower inut) which pulls water in from the lake/river. If you have a lower unit, then the impeller and gasket should be changed out there, too. Personal opinions vary on the frequency, but most subscribe to once a season or every 100 hours. Cheap insurance.

If you have an inboard/shaft/prop (as in a ski nautique or mastercraft), the usually it's just a thru hull fitting in the bottom of the boat.

I'm sure there will be more/better information coming in soon.
 
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Dan Crenshaw

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Joined
Jun 23, 2008
Messages
26
Re: overheating-water pump and impeller?

It has regular outdrive. The engine was making a noise like the water pump was going out like what I remember years ago on a car, a kind of scraping noise. The thermostat was stuck wide open so the temp guage did not show it getting hot.
How do I know if the waterpump is bad? I have already taken it off.
How do I get to the impeller?
 
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Dan Crenshaw

Cadet
Joined
Jun 23, 2008
Messages
26
Re: overheating-water pump and impeller?

I want to look at the diagram of my outdrive but dont know which one I have. I am pretty sure it is original to the boat. 1983.
How do I figure that out? Is there a # on the outdrive?
 
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Dan Crenshaw

Cadet
Joined
Jun 23, 2008
Messages
26
Re: overheating-water pump and impeller?

How do I get to the impeller and how do I know if the water pump is bad?
 
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Dan Crenshaw

Cadet
Joined
Jun 23, 2008
Messages
26
Re: overheating-water pump and impeller?

Great manual! Where can I get a repair manual for the engine?
 
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