Mercruiser 454 computers

[imaflyer]

I have a Mercruiser 454 engine and computer out of a jet boat. I am installing it in my Wellcraft express cruiser w/Bravo3 outdrive. Does anyone know if the computer programming is different between jet and outdrive apps?

 

[Bt Doctur]

serial number of engine and ECM module. is it carbe`d ,injected, ?

 

[imaflyer]

Hmmm, I'll have to do some research on the SN of both the motor and ECM. Perhaps this will help: It is the newer EFI setup...looks just like a bigger version of the Corvette 350 EFI and works just like it with the throttle body in the front and center of the intake manifold. The ECM is not a square, more like a rectangle with rounded corners and about 8 X 5 or so and about 2 inches thick. I would guess that this was an offering from around 2000 to 2005.

 

[thumpar]

Another thing to check is the cam. Some of those jet boats don't run wet exhaust so you could get reversion with a Merc setup.

 

[imaflyer]

Since it came to me complete, including wet exhaust manifolds, the cam should be fine. I sent it out for a possible rebuild (a valve job, new bearings, seals and gaskets) and it came back assembled and running. We've since installed it in the boat and it starts and runs fine, but I have to say that the stock carburated 454 that I removed performed better. Better out of the hole and better top end. We didn't change anything other than the engine. I'm assuming that because this was a jet app that the computer has a different map from that for an outdrive. BTW, thank you all for speaking up...I appreciate your time and attention.

 

[alldodge]

My guess would be you have a MEFI 3 being your listed model year. So far as the map tuning, normally I wouldn't think it would be that much off. If it was placed in a real light speed boat, someone might have monkeyed with the turning. Even with that it should be able to push 300 plus HP. I would suggest plugging in a scan tool and see what kind of readings your getting.

BTW how did you set the timing? To set timing it has to be placed in base timing mode

 

[Bondo]

I would suggest plugging in a scan tool and see what kind of readings your getting.

Ayuh,.... Welcome Aboard,.... I gotta agree with AD,.....

Take a scanner/ 'puter for a boat ride, 'n see what's up, real time,....