how to tell a merc 2.0, 2.4, 2.5 apart visually ...

[bigshrimpin]

yeah . . . I could write a book here. What years are you talking about? It should be pretty obvious.

Heads, carbs, intake, serial number, decals, block difference 2.0L vs. 2.5L (buldge . . . 92 and later).
Search screamandfly.com or get a factory manual. Can't the owner tell you what he's selling???