So long story short I blew a powerhead on my 1998 Merc XRI 150. I traded it in on a rebuilt XR6 150 but soon started having issues with it. The guy I bought it from offered to swap me back my original motor the 98 XRI but he had removed the EFI parts and put on carbs. So I went ahead and did it. So the motor I currently have is a 1998 XRI 150 serial number 0D275859 with carbs from a mid 90's XR6 and NO oil injection. I am not happy with the power from this current setup 52 MPH at 5500 RPMs, same motor before I blew it was hitting 60 MPH at 5800 RPMs the XR6 was even better hitting 62mph at 6000 RPMs. Everything has stayed the same lower unit, prop motor height all the same yet the rebuild with carbs just doenst have the power.
The guy I bought the rebuild from said it might be do to the carbs not matching the block and heads right. They are model WHM 14a
So in my quest to get my speed back I came across a buddy who blew is his 1998 merc 175 EFI motor that will sell it to me at $600, I need a lower unit any how so I thought this might be a good opportunity to get my power back.
I am considering trying to convert my motor back to EFI buy using his motor as a donor but realize his motor blew for a reason so I dont know if this is all worth it and how hard the work would be? I would like to add the oil injection back too but not sure how much of his oil injection I can use or have tested to make sure its good before I go this route. I can send the injectors off for testing\cleaning but I am not sure how much trouble this is going to be? I dont expect to get 175 HP but just get back to where I was before would be great.

My other option is to try another set of carbs to see if that improves my power.

Any help or options will be greatly appreciated