merc 4.3 reliability

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ryanr623

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Jul 11, 2008
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I just bought a boat with a 1991 merc 4.3 motor. Are these reliable engines? Any quirks I should pay attention to, or preventative maintenence for this motor?
 
scipper77

scipper77

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Re: merc 4.3 reliability

I think most would agree that that is a very good engine. It's important that a 20 year old engine has been treated well.
 
Don S

Don S

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Re: merc 4.3 reliability

In the last 25 years or so, the 4.3 is the ONLY V6 used in boats. Only quirk is caused by lack of maintenance, just like any other engine.
 
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ryanr623

Chief Petty Officer
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Messages
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Re: merc 4.3 reliability

scipper77 said:
I think most would agree that that is a very good engine. It's important that a 20 year old engine has been treated well.
Click to expand...

It was gone over by the dealer, everything is good. Boat is in very good condition. These two thing make me think it was taken care of.

Don S said:
In the last 25 years or so, the 4.3 is the ONLY V6 used in boats. Only quirk is caused by lack of maintenance, just like any other engine.
Click to expand...

Gotcha thanks!
 
superpop

superpop

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869
Re: merc 4.3 reliability

I would do a compression check so you have a baseline number to track with regards to compression. My last motor was a 4.3L Vortec and it was good, had around 150PSI of compression in all cylinders, I think that was a bit low, but download the manuals and they will give you the specs.
 
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crewscontrol

Seaman
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Sep 15, 2010
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Re: merc 4.3 reliability

The V6 4.3 is the old 350 V8 Chevy engine with the rear two cylinders removed. It is a very good engine. I have one in my business van that currently has 287,000 miles. It runs perfectly and uses no oil. The valve covers have never been off.
 
zbnutcase

zbnutcase

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Re: merc 4.3 reliability

If you look at head design, it is cyls #3&6 that have been removed :)
 
paultjohnson

paultjohnson

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Jul 29, 2010
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Re: merc 4.3 reliability

My 86 4.3 has been a great power plant. It does what I need it to do, pulls water skiers etc without complaint, and is actually really efficient on fuel use when I want it to be. Never been stranded, very reliable, easy to work on. I would not hesitate to own another...
 
pvmtsux

pvmtsux

Petty Officer 3rd Class
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Oct 27, 2008
Messages
90
Re: merc 4.3 reliability

This engine is a champion. I've owned a couple and they have never given me a problem. As stated before, you just have to take care of it.
 
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