Re: 1989 150 mecury black max XR2
My 88 XR4 is a 2.4 wid a clamshell cowl. I think the difference between them is XR2 is 2.0l, XR4 is 2.4l. XR6 is 2.5l. They are all strong 150's. XR2 and XR4 came with 4 1/4 in lowers. XR6 came with either 4 1/4 or 4 3/4 in lower. Cowls went from clamshell to bucket when the electrical system went from 16a to 40 amp wetback. (both XR4 and XR6)
If it's an 89, it ain't an XR2. If it's an XR2 it ain't an 89. Most of the parts interchange, so you might have to either pull a head, or take detailed pictures of the engine and pull some numbers off'n it, like carb model numbers so we can figure out what you got.
If yer lucky, it's an XR4 with an XR2 clamshell on it. Shave the heads, chit can the advance module and do a custom link n sync on it, maybe do some plug reading and re-jetting, and hang on fer the ride.
hope it helps
john