Mercury 1997 25 EH 0G458399 who made it?

Hi, I own this engine and have been told it is actually a Yamaha or a Tohatsu. Either way it is a great engine. Thanks in advance.

It was designed by Yamaha, but I beleive Tohatsu built them for Merc.

Jeff

It was designed by Yamaha, but I beleive Tohatsu built them for Merc.

Click to expand...

Nope... It is 100% Mercury designed and built.....

Graham!

Jeff

(sorry - this got long and wandered a bit - so please bear with my rambling)

Merc hasn't actually "built" a motor below 40 horses pretty much since the days of Carl Kiekhaefer, but they have assembled a few.

The Mercury and Mercury/Mariner portable line (2 stroke) (not including the Mariner line "built" in Japan between 1974 and 1992) which was introduced in 1986 and included the 6 thru 25 horse models were composed of the following components:

powerheads built by Yamaha (headless "split-block", also called "jug heads")

gears built by Yamaha

ignitions designed by Merc (Thunderbolt 4 (more correctly "Thunderbolt, Type 4 (CD Coil per Cylinder)" - there was a Thunderbolt 1 (Phelon), 2 (Phasemaker), and 3 (CD Pointless))

carbs built by Walbro

gear cases built by Merc (which were also used by Honda until they worked the bugs out of their own mfg process).

Part way through the 1994 model year (often referred to as "1994 and a half" or "mid-94") they made some minor design changes which "Yamaha" incorporated into the mfg process (the most significant change was moving the 9.9 from the 12.6 cubic inch powerhead which was shared with the 6 and 8 hp models, to the 16 cube which until that point had been used exclusively by the 15 horse).

Throughout this time period Yami did not copy any of the Merc (designs) but simply manufactured to Merc spec and shipped the units and parts to Merc's various assembly plants located primarily in Australia, Belgium, Canada and the United States (The Canadian and Aussie plants closed (remaining as "regional headquarters") leaving all the production at the other locations during this time period).

Primarily due to EPA pressures, Merc began phasing out their two stroke line in the early 2000's and had ceased it all by 2005 for the "domestic" US Market (which does account for 40% of Merc sales).

Hand in hand with this, in 2004, Merc had a major falling out with Yamaha. In 1998 Merc had signed a deal with Yami to provide powerheads for Merc's 80 thru 120 horse models (on top of their existing relationship) upto and including the 2006 model years.

In 2003'ish the US instituted "anti-dumping" laws to protect US business from "cheap" products from abroad. In the fallout of this the bottom line was, the cost of a powerhead for Merc was going to go up significantly since an "interim" 22.5% tariff was going on "Japanese outboards AND powerheads" imported to the US. Plus, Merc was getting worried because Yami was starting to steal significant US marketshare from them.

Since still fully 60% of Merc's sales occurred outside the US, with a significant demand for 2 stroke motors, particularly in Asia, Merc quickly climbed into bed with Tohatsu, with whom they had been persuing "joint development ventures" since the mid 1980's.

Since at least 2005, Tohatsu has built four different two stroke models for Merc (all of which are readily available as "new current year models" in Canada, amoung other places).

The 9.9 and 15 horse models which had been around since 86/87 (respectively) are still in production as well as the 25 and 30 horse "Sea Pro" (initially called "Saltwater edition" for a couple of years when Tohatsu took over the mfg of them so they wouldn't be confused with the 25 horse "SeaPro" which was Yami built until that point) - however, now made by Tohatsu to Merc spec (I personally can not tell the difference between a 2012 Merc 9.9 and my 1986 Merc 9.9 - the parts are the same).

Tohatsu in Japan also builds "All" the Merc 4 strokes upto/including the 30 horse model (and they are Mechanically identical to the same horsepower in the Tohatsu and Nissan line).

Merc had ZERO interest in either building a plant to produce smaller 4 strokes, or retooling their existing production facilities - Tohatsu builds them cheaper than Merc could ever hope to and the models were already proven - even at OEM prices a set of decals are less than 100 bucks (plus, with no domestic market for conventional 2 strokes, it doesn't make sense to make them domestically for "export only" when they can be made for less than half the cost at a location close to the intended market).

(**side note - in 2012, BRP (Evinrude) also signed a deal with Tohatsu to mfg a line of portables (3.5 to 15 horse to complement and fill in the gaps with their ETEC line) - this has "ticked" Merc off a little so who knows where production will go if it turns into another Yami-bash).

Merc does built their 40, 50, and 60 horse models, but at an assembly plant in Suzhou, China (of course they build all the parts in the US and ship them over to China for assembly there - NOT).

All 75 horse and up 4 stroke, Optimax and Verado line ARE built in Fond du Lac, Wisconsin or St. Cloud, Florida from "domestic and imported parts" (and while the numbers are not out there you wanna bet that the "imported" percentage far outweighs the "domestic") and for Europe/Asia, at their plant in Petit-Rechain, Belgium.

Merc's electrical systems, harnesses etc, are mfg by Merc at their plant in Juarez, Mexico. (so if you hang a Merc sign on a plant in China or Mexico does that still count as "outsourcing" or is it simply "geographical diversity"?? )

So to get back to your original question....

Your motor was "assembled" in the US.

Merc received a package from Japan (with a Yamaha/Japan return address) that contained a fully assembled (bare) powerhead and a matched set of gears.

They got out the socket set and bolted on a carb from Walbro and an ignition set (maybe produced by Motorolla - just guessing there, but that is who builds their PCM ignitions).

With that together they stuck it on a Merc designed (but sourced) exhaust housing and gearcase and cowlings. Then applied the decals and stuck on a Michigan Wheel (Merc OEM) prop for good measure.

So depending on how you define "made by" -

if you go by % of the mfg components - your outboard is a Yamaha built to Merc spec
if you go by country of assembly, it's American
if you go by the source of all the parts - what the heck, call it made by "the United Nations"

(forgive me, I can not give credit to all the source material here, I simply can't remember all the authors. Most came from Mercury Marine press releases, histories or share holder circulars. Some was derived from articles in BoatUs magazine or general media reporting. The note about Evinrude/Tohatsu was from a 2012 BRP press brief. I apologize if I have missed anyone but I have not directly quoted or reproduced any copyrighted material in whole or in part - this is simply a "jist" compiled from all the various sources, sprinkled with a bit of my opinion)

WOW!!!!!!!!!!!!!! As #3 daughter would say "Awesome"

Thanks for clarifying all that, as I knew you would.

Jeff

Wow! Thanks for the information. The hunt for profit makes for global bedfellows I guess. So it is a Yamamerc. Newer ones would be Yamamercahatsu. Either way it is a great engine.

I know that the 25hp blocks are USA made in Wisconsin as told this by Mercury local factory rep. Below is little history on that block.....

In the mid-1980’s, Mercury Marine started its largest and most systematic field study in its die cast Merc 25 block to
evaluate a family of copper-free hypereutectic aluminumsilicon alloys called Mercosil technology. Mercosil is an
acronym for Materials Engineered for Resistance: Corrosion (copper free) and Wear (silicon). After accumulating
1,000,000 field hours with test fleet of engines with no failures attributed to the alloy, the decision was made to go
into full production in 1994 with Mercosil for the Merc 25 block.
The Mercosil Merc 25 engine replaced a very successful engine block that had chrome plated bores, and was in
production for over 20 years. The only flaw inherent in the previous Merc 25 with chrome plate bores (besides cost of
manufacture) was its susceptibility to fatal damage when large debris was ingested by the engine. The Mercosil Merc 25 is tolerant of ingested debris.

Ok, I had to go diggin' here.

This is a table from some of the 2005 hearings into the lawsuit involving Merc and Yami over the dumping of cheap powerheads (which merc liked as long as they were only being dumped on them). The transcripts are hundreds of pages long with endless footnotes and redacted parts. Anyhow, this table came from the discussions/arguements about the agreement signed in 1993 between Merc and Yami regarding the joint development and production of certain powerheads and complete motors.

This table shows which horsepower for respecitve models were built using Yamaha produced powerheads in the 2003/04 model years. (these pre-dated the Verado line).

Following the table is a scan of some of the notes from the same hearing transcriptions. It clearly states that joint production of the 25 and 40 horse powerheads were still covered by the (1993) agreement (this was in 2005 when the transcript was made) - and it (the agreement) ultimately continued to 2006.

So while the factory rep who told you this may have been partially correct (some other notes tend to indicate that certain blocks were in fact shipped back and forth between the US and Japan in various states of "completeness") it is abundantly clear from the court records that, at minimum, the 25 and 40 horse models were still bound to the terms of the 1993 agreement which would have prevented Merc from designing and producing them "entirely" themself - Yami must have had some input (either engineering or production wise - and if 'merc' designed it, Yami would have had to at least built some of it)

Anyhow, here is the table and some of the footnotes (on the table there is a "2" (footnote 2) which got cut off on my scan). Footnote 2 applied to motors that were "engines produced from "excluded" powerheads from Japan" (those not subject to the anti-dumping lawsuit) - all others were "produced using imports of "subject powerheads" from Japan. (so when you get rid of all the Merc models made with Yamaha powerheads, there doesn't seem to be too much left in their line-up)...





(what I should have added initially)

In 2004 Merc sued Yami because Yami intended to increase the price of their powerheads by a little over 90% (above the 20-something % tariff that had already been placed on them by the US). Merc sued to enforce the price that had been negotiated in the 1993 agreement. Since this agreement required, specifically, the 25 and 40 horse models to be jointly produced at least until 2006, it is more than unlikely that Merc violated the very agreement they were trying to enforce in court by designing and completely building the 25 horse "Mercosil" motors which were first produced part way through the 1995 model year (production numbers 0G202750 and above) without any input or mfg from Yamaha.

Thanks Graham. Looks like the proof for the pudding.

Ultimately it doesn't really matter "who" built the motor.

What does matter is this -

The portable outboards (6 thru 25 horse) sold as Merc's or Merc/Mariners which were built between 1986 and 2005 are without question absolutely the best outboards (or any hp or mfg) on the planet - even including current "hi tech" models.

The combination of the engineering that went into the split block design combined with the T4 ignition and probably the best small engine carbs ever made, resulted in outboards, that with "minimal" care will outlive the lives of their owners and some of their owners decendants.

They start when you pull the rope, give you the best horsepower to weight ratio available, require nothing more than fresh gas combined with a new spark plug and impeller every couple of years.

The cost of an oil and filter change on a 9.9 horse 4 stroke (which must be done yearly) exceeds the cost of the amount of 2 stroke oil you will burn in one of these even if you are pushing 200 hours use a year and if you run them head to head, the two stroke will kick the snot of the 4 stroke just about any way you want to measure it - plus, it's about 50 pounds lighter on a model to model basis (so your 4 stroke gas "savings", which only occurs below 3000 rpm is eaten up pushing around the added weight "all the time" - and yes, 50 extra pounds on a 200 lbs aluminum boat is "ALOT")

There is nothing out there that compares to the durability of one of these little 2 stroke Merc's.

Take care of it and when your grandchildren have used up the last of the worlds oil, maybe it can finally be retired from "active service"

Can't agree with you more. My brother has a Suzuki 25 4stroke, it feels anemic compared to my Merc. I have more torque and usable horse power. Not to mention his annoying rev limiter that makes you go back to idle before accellerating again. I am glad to own this "two smoke" engine. Would love to hand it over to my son some day and watch him enjoy it for years.