Thermostat Removal on Mercruiser 4.3L V6 Alpha

philsislands

Cadet
Joined
Nov 8, 2012
Messages
8
It averages around 32˚C - 36˚C (89˚F - 96˚F) in the summer. And my question is, would it be ok if i removed the thermostat from the housing and to just keep the water continuously flowing around inside?
Has anyone done this? Your thoughts?
Thanks
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,915
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

It sort of depends on the exact vintage of your engine. Newer versions with the electronic engine controls will want a certain temperature range in order to operate the engine properly.

So, generally it is not a good idea to go without a thermostat. Is there a problem that you are trying to solve by removing it?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

It averages around 32˚C - 36˚C (89˚F - 96˚F) in the summer. And my question is, would it be ok if i removed the thermostat from the housing and to just keep the water continuously flowing around inside?
Has anyone done this? Your thoughts?
Thanks

I've run my boat in 40?C +, and I NEVER run without a thermostat.

If you remove the thermostat the engine will never reach the correct operating temperature. That will lead to a build up of sludge in the oil, and use excess fuel (choke may not come off completely). It could also mean the cylinder temperatures are low and uneven, leading to premature wear in the block and on the pistons.

If you are having overheating problems, look elsewhere for the problem, like the water pump impeller, the exhaust elbows and manifolds... With the water in the Philippines being so warm (I know, I've dived Puerto Galera. :D), you may need to put a 'Japsco' style pump on.

What is the year (or serial number) of the engine? The 4.3 litre V6 started in 1985 and is still in use, so there have been many changes over those years.

Chris......

Hey Ted, love the last line of your signature... :D :D :D
 

mercs4mark

Petty Officer 2nd Class
Joined
Dec 19, 2010
Messages
141
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

Not a good idea ....the engine needs to be run at the operating temperature to perform correctly
 

britisher

Petty Officer 1st Class
Joined
Feb 23, 2012
Messages
369
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

The thermostat setting for a 4.3 V6 mercruiser is 160 degrees F, so I understand. Even if the outside water temp was 96 F, it would still be running cool. Too cool is as bad as too hot.
 

philsislands

Cadet
Joined
Nov 8, 2012
Messages
8
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

Thank you all for your input. It's a 1996 model installed on a 1997 Celebrity 180.
Have not run it yet as i just got the boat from a friend. opened the thermostat housing and did not find a thermostat in it so i thought of asking before i put it back together.
No issues of overheating yet as i just changed the exhaust and all the hoses.
 

philsislands

Cadet
Joined
Nov 8, 2012
Messages
8
Re: Thermostat Removal on Mercruiser 4.3L V6 Alpha

Thank you all for your input. It's a 1996 model installed on a 1997 Celebrity 180.
Have not run it yet as i just got the boat from a friend. opened the thermostat housing and did not find a thermostat in it so i thought of asking before i put it back together.
No issues of overheating yet as i just changed the exhaust and all the hoses.
 
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