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Mercruiser 383 ECM problem

N

nautiluss

New member
Hi everybody,

in 2009 we installed Mercruiser 383 MAG MPI in our boat. Bravo 3 package with freshwater cooling (half system). I think seller added heat exchanger.

We had ECM failure this year. I docked the boat and turned off the engine. The next day it did not start. No beep and no fuel pump prime at ignition. It cranks but the engine does not start.

I tried to replace ECM from other 383 (owned by neighbor – no freshwater cooling). The engine started and run fine at dock. We need to buy new ECM.

In the part list two options are available:
864273T07 – ECM Engine Control Module
865008T04 – ECM Engine Control Module, freshwater cooling mode

The engine was purchased in US. Since the dealer has added heat exchanger, I am confused. What is the difference? Thermostat holds the water temperature at approx. 175 deg. F.

The labels on my dead ECM:

6.2L Bravo 8M2003689
8M2001111
ECM0708
03-04-2009
YO000RSE
8M2001111

Need help, please.
Dealers in our country do not know the answer.
Three technicians was already on boat, but no success.
 
Last edited:
You can always try mercruiser tech support for a difinitive answer...


My best guess is that the only difference is the 'tune' loaded into the ECU...the fresh water cooled version will run a few degrees hotter than the raw water version...with the heat exchanger, I would go for the FWC version of the ECU. I am sure the difference in economy/performance is small but with fuel costs nowadays, every penny helps...
 
The difference between a "Full" and a "Half" fresh water cooling system is that with a half system, the exhaust manifolds and elbows are cooled with sea water. In a Full system, the exhaust manifold is included in the "fresh" loop. As a result, Half systems are cheaper since they can use a smaller capacity heat exchanger than a full system. With both "Full" and "Half" for most manufacturers, the elbows are sea water cooled. Crusader includes the Elbows in the Fresh loop and injects sea water into the exhaust stream purely to cool the exhaust gases and get rid of hot sea water from the heat exchanger.
 
makomark said:
You can always try mercruiser tech support for a difinitive answer... My best guess is that the only difference is the 'tune' loaded into the ECU...the fresh water cooled version will run a few degrees hotter than the raw water version...with the heat exchanger, I would go for the FWC version of the ECU. I am sure the difference in economy/performance is small but with fuel costs nowadays, every penny helps...
Click to expand...
I believe you are right. Just wrote an email to tech support, to be sure. Thank you for your answer.
 
Last edited:
sandkicker said:
The difference between a "Full" and a "Half" fresh water cooling system is that with a half system, the exhaust manifolds and elbows are cooled with sea water. In a Full system, the exhaust manifold is included in the "fresh" loop. As a result, Half systems are cheaper since they can use a smaller capacity heat exchanger than a full system. With both "Full" and "Half" for most manufacturers, the elbows are sea water cooled. Crusader includes the Elbows in the Fresh loop and injects sea water into the exhaust stream purely to cool the exhaust gases and get rid of hot sea water from the heat exchanger.
Click to expand...
I understand the difference between the two systems. I just don t know which ECM is right for my engine.
 
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