40HP Mariner model questions

Howdy from a new user. Stumbled upon this forum and it looks great! I recently picked up a used pontoon with a 40HP Mariner. She runs great. The tag says "Built in Japan for Mariner International" The serial number is: 676 S 10147.

Can anyone tell me what year it is? From what I can gather, it appears that it was made by Yamaha.

I'm also interested in parts for water pump/impeller, oil/gas ratio, and a prop. The prop that is on it is a pin drive, non-thru hub exhaust and appears to be a 11.5 X 12 and I am having a hard time finding something close as a replacement.

I thank you in advance for any help you can provide..........Mark

Sorry, totally missed your post.

Yes, it is a Yamaha built (for Merc) 1977 "A" model Mariner.

Parts can be somewhat difficult to come by for these particular models.

There is no longer a "waterpump kit" for these, some parts are just no longer in stock but the impeller and some of the gaskets/seals are still available from a Merc dealer - just don't let your heart stop when you see that the impeller alone sells for almost 58 bucks.

It will mix at 50:1 with modern TCW3 rated marine oil and regular unleaded gas.

I checked both Quicksilver and Michigan wheel prop charts and don't see anything currently listed for the 40 horse with pin drive - you may be stuck searching Ebay or contacting a recycler...

Thank You very much for the reply! I will start my hunt for an impeller!