2005 4.3 engine question

sullified

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May 24, 2013
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I bought a 2005 mercruiser 4.3 the engine is missing the ecm is there anyway to change the motor to a carbureted motor and what would I need to get to make this motor run.The reason I'm asking is there is no numbers on the motor to figure out which ecm to run someone told me I could by a carb a four barrel intake and a thunderbolt distributor to make this motor run any help before I go and spend more money ? oh ya one more thing its going in a older boat with a alpha one outdrive same gear ratio
 
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Don S

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Re: 2005 4.3 engine question

Before you go to all that trouble look in this location for a Mercruiser serial number tag. It's often over looked.

Eng sn location.jpg

Might post a picture of your engine, lots of other things could change other than the intake, carb, and distributor.
Wiring harness, fuel pump, linkage, brackets ...............
 

Tail_Gunner

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Jan 13, 2006
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Re: 2005 4.3 engine question

Top Quality Source for Boat MEFI ECU Tuning | CO, KS, OK, TX, NE, AR, MO | MEFI Tuning

For you owners that have the VOLVO driver package we have a package to convert your MPI/VOLVO systems to the DELPHI MEFI 4B controller. This includes ECU and all the necessary wiring harnesses. Additionally, we have packages to convert your MerCruiser ECM555 controlled engine commonly found on the 525's to the proven MEFI 4A or MEFI 4B system. Don't be locked into an expensive and limited tuning source.

Those guys can do a conversion for you, That is going from a merc 555 to mefi. Just a option for you
 

Don S

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Re: 2005 4.3 engine question

Those guys can do a conversion for you, That is going from a merc 555 to mefi. Just a option for you

Why would anyone want to do that? MEFI is outdated
I would have to suspect it would be cheaper to install a new 555 ECM, than all the wiring and MEFI harnesses plus the ECM needed to convert.

My biggest question would be WHY the ECM was missing to begin with?
 

Tail_Gunner

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Re: 2005 4.3 engine question

Why would anyone want to do that? MEFI is outdated
I would have to suspect it would be cheaper to install a new 555 ECM, than all the wiring and MEFI harnesses plus the ECM needed to convert.

My biggest question would be WHY the ECM was missing to begin with?

Actually a mefi4b is far more capable than any marine engine can deal with...That old mefi design is still pretty the same than anything being used today In the right hands it can do anything you would ever think of for engine mgmt......And programable at the drop of a hat.
 

Don S

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Re: 2005 4.3 engine question

Programmable? maybe, if you know what your doing, or paying someone to do it. But it's not necessary, or cost effective.
MEFI is an outdated system an not used by anyone anymore.

It might work great for race boats with all the high tech expensive stuff associated with it. But boaters that post here want it to run, not spend $$$$$$$ on programming and experimenting.
 
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achris

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May 19, 2004
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27,468
Re: 2005 4.3 engine question

555 ECU for the 4.3 has been the same from about 2002 to current.

You have 4 choices for the ECU on a 4.3 engine of that year.
1. Alpha drive, standard cooling
2. Alpha drive, closed cooling
3. Bravo drive, standard cooling
4. Bravo drive, closed cooling.

You have already said it's going to be in front of an Alpha drive, so, is it standard or closed cooling?

Although a 555ECU is not cheap, it will be cheaper than trying to put a carb (and all the other stuff you'd need to make that change) or putting another system on. Your engine already has all the rest of the gear on it to be running with the 555ECU, why go through the pain and suffering of trying to make something else work....

Chris........
 
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