posted 11-23-2004 06:14 AM ET (US)            

It is relatively easy to figure out what four-stroke was made where and by who: The only four-stroke engine, outside of the new Verado 200-275-HP models, which is made in North American (by either Mercury or Bombardier) and does not contain a powerhead imported from Japan (either from Yamaha or Tohatsu or Suzuki) is the 25-HP model from Mercury. Every other four-stroke outboard engine sold in the U.S. has a powerhead imported from Japan.

Bombardier is re-badging Suzuki engines. Mercury buys powerheads from Yamaha and also from Tohatsu. They also buy some complete engines from Tohatsu and Yamaha.

The long answer:

There is much cross-breeding between Mercury and Yamaha in the four-stroke engines. The majority of this involves Yamaha providing Mercury with assembled powerheads.

A short history: in 1993 Mercury or Yamaha partnered to develop four-stroke outboards that both would sell. This co-development and co-manufacturing arrangement lead to several four-stroke engines from 9.9-HP to 50-HP.

The agreement provided that some components would be manufactured by Mercury and some by Yamaha. These parts would be assembled into complete engines. Mercury concentrated on engine blocks, and Yamaha concentrated on cylinder heads. This deal was for five years, but some of it continues past 1998 to this day. It may be that Yamaha still buys some engine blocks from Mercury for certain engines, and Mercury still buys some cylinder heads from Yamaha for certain engines.

Mercury says that some of the powerheads it is importing from Japan "are a result of co-production and co-development that contain a significant amount of U.S. contents" and these are "coming in from Japan after being assembled between Japanese and U.S. producers." That sounds a little like lawyer speak to me. I think the first statement above makes it clearer: everything but the 25-HP comes from Japan.

Now by "powerhead" I guess this excludes the fuel induction system, as
Mercury also developed fuel-injection technology for these four-stroke engines. They get the powerheads without any fuel system, and they add their own fuel-injection and computer controls, etc.

It is something of an urban legend around here that there is an engine (a 50 or 60-HP four-stroke, perhaps) which is assembled by Mercury into a complete powerhead and shipped to Japan to be finished as a Yamaha engine, and that Yamaha engine is then re-imported to the U.S. and sold as a Yamaha product. I am not sure I believe this. I think the Mercury content in any Yamaha engine may be limited to the engine block from the co-development deal of 1993.

In addition to all of this, Mercury purchases entire four-stroke powerheads from Yamaha for their 75, 90, and 115-HP four-stroke engines. These powerheads are not part of any co-development venture. They are entirely Yamaha powerheads made in Japan. Mercury does add the fuel-injection to them, and, of course, the midsection, lower unit, and cowling.

In strong part due to extremely urgent demand from the Boston Whaler dealers, Mercury for a while was buying complete 225-HP four-stroke engines from Yamaha and painting them black, adding Mercury decals, etc. This arrangement provided for at least 3,000 engines which Mercury sold mainly to their OEM boat builders for packaging with new boats, until the Verado was introduced. I don't know if anyone ever bought a loose 225-HP Mercury four-stroke. (That would be an interesting question to track down, anybody have one?)

What I find interesting in the arrangement is the division of the work provided in the 1993 co-development arrangement. I am certain the engine block in a four-stroke is quite different than in a two-stroke, but, making a uninformed guess, it looks to me like it would be less of a leap into new technology to make a four-stroke engine block than it would to make the cylinder head. The cylinder head in a four-stroke engine is very different than the cylinder head in a two-stroke engine. The four-stroke has valves and camshafts, while the two-stroke has none of that. On the other hand, it may have been that the division of the work was made to account for the manufacturing capacity available to both partners, and, apparently, Mercury could make the engine block with better efficiency than Yamaha, and vice versa on the cylinder heads.

In any event, the reliance on imported powerheads from Japan for use in four-stroke outboards is quite amazing. Until Mercury began production in Fond du Lac of the new Verado, apparently the only complete powerhead produced domestically was this little 25-HP model.

posted 11-23-2004 07:19 AM ET (US)            

I think that Bombardier is importing 6-HP and 8-HP four-stroke engines of their own manufacture, but they make them in China.

Also, to clarify on the 50-60 HP four-stroke from Mercury, this engine was in the co-development deal with Yamaha, which had a minimum five-year co-manufacture, but now Mercury is making this engine on its own. After 2000 the engine is made "completely in Fond du lac," which I would assume means that Mercury is casting the powerhead components themselves. Mercury states this engine is "a completely domestically-produced engine."

posted 11-24-2004 12:31 AM ET (US)            

I was not necessarily saying it was less Yamaha. It's their design. And they are the ones that support it with parts.

It's just if you have some bias that you have to have something that's all from some manufacturer, you are probably out of luck.

And, something like a starter motor is not surprising. But a flywheel seemed a little strange to outsource. Not all that much to it.

I suspect you mean mix their own alloy at casting time from metal they buy already refined in the case of Mercury. It's a very big op to refine aluminum economically from the ore. You will probably find that every single manufacturer who casts their own aluminum parts spec it themselves, have their preferred alloy that they mix and pour. Though in a way I'd like to see more known alloys used.

posted 11-24-2004 09:25 AM ET (US)            

Mercury calls their alloy XK-360. I don't know if there are any metallurgical standards that recognize that name or number. It may be considered a trade secret. As you say, one might have more confidence if it were a standard alloy with known properties.

Yamaha does a similar thing. They say their engines use YDC-30 alloy.

In terms of branding an engine as your own, this become more difficult if major components of the engine are purchased from a vendor who also makes outboard motors of very similar or same design with the same components.