150 optimax block swapped out for 175 EFI - good or bad?

[Ho06wrx]

Need some help deciding if this motor is a good investment. It was a 2002 150hp optimax that blew the powerhead. Owner tells me that they had swapped out the entire block with a 'new' 04/05 175hp EFI and have put about 60 hrs on it since with no problems. Rest of the motor is still the 02 opti. I'm told the blocks are fully interchangeable provided it was done properly.
What are peoples thoughts about this?
The price is right but I'm thinking it's too good to be true... any advice is greatly appreciated.

 

[Chris1956]

An Optimax and an EFI motor are two different animals. Optimax is a Direct Injected 2 cycle outboard motor. As such it will use lots less fuel and oil. The EFI motor is simply a carb style OB, with fuel injectors instead of carbs. It will have about the same fuel usage as the carb outboard.

 

[Chris1956]

Let me add to my last post, to be clear. An EFI motor will use a throttle body-type fuel injection, versus, injection directly into the combustion chamber, as the Optimax does.

 

[Ho06wrx]

I sorta understand the differences between the opti DFI vs EFI vs carb...

but what I'm concerned with is the current owner of this outboard had the ENTIRE block completely swapped to a newer EFI motor while using the remaining 02 "optimax" parts (I realize it's no longer an optimax but you get what I'm sayin...). Aside from the block, everything is still the original 2002 optimax.

is this acceptable? reliable?
Would you consider buying this motor or should I run and not look back?

 

[Dukedog]

Chris, think hes sayin' complete drop on power head on tha "Opti" clamp, down housing, trim and gear case.....So yes ya can. Those parts are fine since both are 2.5's with probably only difference being tha tuner......Sure wouldn't give a "premium price on tha motor value part though". Especially if its titled/registered separate from tha boat as in some states.....

 

[Chris1956]

Duke, That is fine. I was concerned that the OP thought he was getting a DI motor, with it's efficiency advantages.

 

[wired247]

By saying "block" I think he means powerhead. No big deal. Basically now its a Mercury 175 EFI with a opti sticker on the outside. Probably run longer than one of the hair dryer engines anyway.