Mercury lower unit cross reference

[John Painter]

I recently purchased a bigger boat that came with a 20” Mercury 40hp EFI engine model 1A40311BZ and serial 1C249130 which has a blown lower unit, the upper is excellent. I’ve had a hard time locating lowers at least 2.00:1 so am wondering if other serial ranges with different gear ratios will work on it.

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