Hello Alan, and welcome to NSR-WORLD!

Technically, the '88-'96 motors are all interchangeable, only the 1987 won't easily transfer, as it has solid engine mounts as opposed to the later models' rubber mounts. There are however a number of differences to sort through, such as GPS (Gear Position Sensor)/neutral switches, A/C generator harnesses, ignitor coil harnesses/flywheels etc. Just make sure not to mix-and-match model parts, no matter how similar they may look, as it can lead to issues. (I.e. use all 1989 MC18 [R5/6K] OR '90-'93 MC21 components, including the carbs, air correction, and PGM.)
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!