I purchased a rebuilt B1 XR lower and it shipped with an IMCO bearing carrier which I'm told is a bigger bearing vs the Merc. My port side drive has a Merc carrier bearing. Will it be ok to run Merc on one side and IMCO on the other? Will I see a performance difference between the two drives? I just don't want to put this all together and then have the motors off a 100 or more RPMs from each other on top of what they are naturally (50 or so) and then not be able to send the lower back because I installed and ran it. Thoughts?

I was just comparing the two yesterday. The IMCO does indeed have a bigger bearing on the prop shaft. It's about 2x's the depth as the Merc bearing. Will you notice a difference, doubt it. Is the IMCO better? I'd say yes, but by how much I don't know. I'll post a picture of the two side by side later tonight.

as long as ratios and props are the same, the tiny bit of different rolling resistance between the 2 carriers will not be noticeable. people with shaft boats change 1 motor and leave other till next year. 318 on 1 side. 454 on other. same props, same trans ratio, only diff is throttle lever location when running.

Yes everything else is the same. Thanks for the replies.

I'm off to sand and paint my other lower so it will look nice and shiny like my new (rebuilt) one. Hope to have everything back together and hitting the water this weekend!

Thanks I have them side by side so I see there is a difference. I was just more interested in performance/operation continuity between the two. Sounds like I shouldn't have any issues running Merc on one side and IMCO on the other. Thanks for the reply.

I have one merc and one imco as will. The merc one was drilled and tapped for a prop anode but the imco is not. Why and can it be done with out messing it up.