225 opti computer into 200 opti? Direct swap? Other changes needed?

[RocketScientist]

The PCM (propulsion control module, aka computer) in my 2006 3.0L 200 Optimax (SN: 1B229529200DTS) has died and needs replacing. The shop (certified Mercury Marine dealer, great reputation, very knowledgeable staff) tells me that for only $50 more I can get the computer from a 225 optimax, and that it will drop right in and run fine with no issues. They claim there are NO other differences between the 225 and 200 other than the computer programming, and there will be no issues with the 'upgrade' (other than my newfound 25 hp). I can't help but think maybe there are other minor differences between the two motors (port size, reed size, heads, injectors, etc). My concern being that putting in the 225 PCM might cause problems as a result (running lean/rich, running too hot /cold, poor idle, poor off-idle transition, etc) which may affect longevity/reliability.

Bottom line, if there really is no other difference other than the PCM between the two motors, then I'd be a fool not to take an extra 25hp for $50. But an extra 25hp at the expense of my motor isnt worth it. Any info you may have is appreciated.

[rocketman6965]

Welcome to BBC. You are DEFINITELY going to need serial number to get an accurate answer. Good luck.

[RocketScientist]

Welcome to BBC. You are DEFINITELY going to need serial number to get an accurate answer. Good luck.

Thats a very good point, thanks. I have the engine SN written down in notebook at work. I'll add that to the post first thing in the morning. Thanks again.

[Savage]

Get a PCM for a 200 HP.....

[RocketScientist]

Get a PCM for a 200 HP.....

Thanks for the feedback! Have any more background/context for that?

Also, added serial number of motor (SN: 1B229529200DTS) to the original post

[JOE54]

ign systems will have to be exact same for it to work (coils),looking on merc site there is no 200 /225 powerheads with same part num (interchange) porting in block of 200 will be smaller and you will not gain 25 hp with pcm swap , been there seen that , tested 05 200 with 225 pcm change only O rpm gain ran and no better mph , try it before you buy it JOE

[Savage]

Thanks for the feedback! Have any more background/context for that?

Also, added serial number of motor (SN: 1B229529200DTS) to the original post

The two motors are different, so install the CORRCT PCM for your motor.

[RocketScientist]

The two motors are different

I mean, that's literally exactly what i was asking: if the motors actually ARE different, other than the PCMs. If the only difference is the PCM (as the mercury mechanic told me) then theres no reason not to use the 225 PCM. If there ARE other differences between the two like you state then it's probably not a good idea. So I am trying to find out IF those differences exist and if so WHAT they are.

Just to be clear, I'm not arguing with you at all. In fact we agree, my default is to stick with the 200 PCM unless I can convince myself there are no other differences. I'm just looking for additional information to either confirm my gut instinct, or confirm what my well-respected, trained and certified mercury mechanic is telling me (that there are NOT any differences beyond the PCM). I appreciate your input, and if you have any specifics or details as to the differences between the motors I would be very appreciative to hear them. I'm just trying to make an informed decision so I'm not in a situation where my choice is to trust one guy (my mechanic) or trust some other guy (you) without any information of my own as to which is right.

[Savage]

The motors ARE different. Post #6 discusses this. You will see no gains.

[FastCat04]

Savage and Joe54 are steering you correctly. Just look up the part #'s for the following items on a 200/225/250 and you'll see at the very minimum the following differences between all 3 engines.
Pistons
Crank
Cylinder Heads
Cylinder Block (ie..port timing)
Reed block
Intake plenum
Throttle body
Fuel system/rails/cooling circuit

I too looked for a simple 'bolt on' 25-50hp...but the only simple & reliable bolt on mod is either: 1) new powerhead 2) complete new outboard

Stick with Savage's recommendations !

[RocketScientist]

The motors ARE different. Post #6 discusses this. You will see no gains.

Yes I see that post, but that wasn't written until AFTER you'd already made yours telling me not to do it. So I thought you might have some information yourself as to how or why they are different, which is why I asked my follow-up (again, all before post #6 was written). Considering you were against the idea before Joe54 chimed in with his info, I assumed you had details yourself about what differences if any there are between the two, and was hoping you would share them in case there was additional/different info to what Joe54 shared. Just trying to educate myself. thanks again.

[Savage]

[EuropeanAM]

Definitely different (porting in block will not support 225 fuel curve). Get the correct PCM or have yours repaired.

[joby1]

Definitely different (porting in block will not support 225 fuel curve). Get the correct PCM or have yours repaired.

listen to this mans advice!!!!!!

[Savage]

listen to this mans advice!!!!!!

and post #4,#6,#10.........

[EuropeanAM]

and post #4,#6,#10.........

Absolutely!