Mercury 150 hp needs lower unit

[Don Mac]

I've got a Mercury XR4 Black Max 150 hp motor with Ser#0C198662 on a boat I just purchased which needs a complete lower unit. It has an 8 spline and I think a 20" shaft (since I measure 19" from bottom of transom mount to cavitation plate). That's all I know for sure at this point. From various info gathered so far I think it is 2.4L, 1.78 gear ratio but don't know the year. I've looked at several used lower units for sale and it looks like most will bolt on from various year models and HP ranges, and I see 1.78 to 2.0 ratios mainly. Can someone tell me what year model from the ser#, and how specific I need to be and if there is any info I have wrong or need to know before ordering one? Thanks.

 

[oldman570]

Re: Mercury 150 hp needs lower unit

From the sr# your motor should be a 1989 Merc 150. As for the LU fitment, there should be other motors that will fit on your motor Maybe ones from around 1987 up to around 1992 or 94. You'll have to research the part# for the driveshaft and see what others it will fit.
Got to start somewhere.
Oldman570

 

[Faztbullet]

Re: Mercury 150 hp needs lower unit

From various info gathered so far I think it is 2.4L,1.78 gear ratio

It is a 2.4L motor and if it has the original gearcase(4-1/4 DIA) it is a 1.78 ratio. Only use a 2:1 ratio on this motor and a new one can be purchased from SEI for $895. Any of the V-6 150's from 1982-1996 with stock unit will fit and you dont want the early XR4 gearcase as pinion bearing wont live in them on a heavy boat..

 

[Don Mac]

Re: Mercury 150 hp needs lower unit

Thank you both for the input. I feel more comfortable looking for the correct replacement now. I checked SEI and it looks like it may be the best option since I can get a new one for not much more than a used one. It may be aftermarket but a 3 year unlimited warranty for any mishap is a great selling point for what must be a good product. Thanks again to both of you. Don Mac