Year of manufacture is meaningless for servicing/valuing an old Tohatsu OB. The M40D came out around 1992, so the C is really old. You could call Tohatsu America at 214 420 6440 and they might be able to help you determine year of manufacture for nostalgia.
Thanks for that insight, however, I just spent over $300 on a carb repair from a so called reputable Tohatsu dealer, only to have one of the intake cowling bolts found rattling around in the cowling and the idle RPM appear to be excessively high. I'm trying to take this matter up with this dealer repair shop, however, knowing what year this motor is will be helpful in finding the correct repair manual. I'm not looking to value it, but want to take on self performing repairs so as to not get ripped off like I just did by paying excessive dealer shop fees for lousy service.
They charged me for 3 hours at $95/hr to inspect and tell me the main jet had fallen out and they reinstalled in without so much as any other work involved. I had also requested the lower unit lube be replaced but they failed to even perform that task.
I'm okay with self performing most task, and I only took the motor into this dealer since the motor was experiencing hard starts and low idle rough running while I was actually on the water, and on the advice of a nearby shop who referred me to this dealer I decided to trailer the boat and drop if of in hopes of getting good service and a valuable once over of the motor, but apparently this was not what I paid for, in spite of filling out the work order form in such a manner as to request a complete tune up in addition to the trouble shooting of the carb issues. This same dealer/repair shop has no mechanic on duty on weekends...go figure...