"Hey Jeff,
I'll
"Hey Jeff,
I'll see what I can put together for you here (this will be kinda long)- some general background and then the more specifics on the 30/40 horse models.
In the 1975 Merc and Yamaha entered into some type of joint production agreement mostly to compete with OMC who was "king of the pile" at the time.
The US government killed the deal in 1983, but Merc and Yami continued to work together closely, with Yami supplying powerheads and gears for most Merc models well into the 1990's, in addition to continuing to produce the bulk of the Mariner line.
Yamaha has always engineered their motors completely, starting with diagrams and working up from there, while most other builders kinda cobble things together to see "what works".
Because of that, Yamaha tended to turn over alot of designs quickly which left them with lots of parts etc that they no longer used on their own motors due to design advances.
Merc didn't really have a presence in the Asian market although they built motors in Belgium and Australia. On the other hand, OMC was producing motors in Hong Kong and had a pretty good thumb on sales in region.
So Merc got Yamaha to produce the Mariner line (100%) primarily for sales in Asia. That allowed Merc into the market with budget freindly motor and gave Yami an outlet for their excess parts.
Every Yamaha built Mariner was a carbon copy of a Yami model that had usually ceased production. So while well engineered, it was "technology wise" outdated the day it came off the production line (much the same as the Force line - but significantly better quality).
The 30 horse Mariner was introduced in 1979, the 40 in 1977. Yamaha produced both models until 1994 (Merc undertook a major model change for most motors in the 94/95 line-up)
The 40 horse Mariner was a super popular model and many were sold in North America as well as Asia and Europe (in Europe the Mariner line was outselling the Merc line).
So in 1989 Merc decided to get themself completely in on the action and began producing 40 horse Mercury/Mariners (just Mercs with the Mariner stickers/colour).
So between 1989 and 1994 there was both "flavours" of Mariner 40's out there. The 30's had a distinct (break). Prior to 94 they were Yami's, and Merc's from the 95 model year on.
Technically...
The 30 horse Mariner was based on Yami's own models 30AM, 30AE, 30AEM for the entire production run. This was not a "intially" a discontinued Yami, it was identical to the model Yami sold during the exact same time frame (1979-85).
The 40 horse is the one that came out in a few different designs.
1977-81 the 40 "A" model Mariner was a 40AM/40AE/40AEM Yamaha. This was a single carb, breaker point ignition, ABOVE prop exhaust (pin drive style prop).
During the same production run 1977-81 the 40 "B" model was also on the market at a slightly higher pricetag. This was based on Yamaha's own model 40B (1977-79) which was only available as a jet drive.
This was also a single carb, but had the option of a Yami CDI magneto ignition system (as an alternate to points which was also available in the "B" model) plus Thru-Hub Exhaust.
In 1981 the most prolific 40 horse Mariner, the "C" was introduced. There were 3 design changes during the course of the C's production.
The early "C" models were a twin carb, CDI ignition, thru-hub exhaust model that ran pre-mix.
In 1987 they introduced the "C" model with the Auto-Blend option. It was simply the early C motor, with addition of the inline oil injection - we all know how the "Auto-Blend" story played out.
In 1989 they introduced the C model with the gear driven oil injection pump (similar design to the style Merc continued to use for years) - still a twin carb, CDI model.
There was one additional 40 horse Yami/Mariner produced between 1988-90 - the Marathon model. This model was based on Yami's model 40G which was produced in 1982 and I have no other details on the model at all.
And now my brain hurts and my fingers are sore, so I will end this very long winded post...
"
