"Name That Outboard"

[mac19f]

GRM also known as a Rossi. 350cc. I believe this is the first one run in this country by Rossi himself at Cypress Gardens.

[Mark Suter]

This GRM motor was also raced by the Thirlby PRO racing team after purchasing it from Guiseppi Rossi.

Back to the prior Yamato motor for a second... this special kilo lower unit was the very one that Sean McKean set numerous world speed records with using a number of different displacement Yamato powerheads. It really has no link to this third-port 250 motor but I had to find a place to display this important piece of racing history.

[J-Dub]

How long ago was Sean running that unit? It had to have been prior to '95.

J-Dub

[Tomtall]

Well --------------- Greg McCreery is correct! It is a Rossi 350. Great Job.

[Mark Suter]

How long ago was Sean running that unit? It had to have been prior to '95.

J-Dub

J-Dub, thanks for asking. I went back through my correspondence with Jim McKean looking for your answer and found my earlier statement to be quite erroneous. The only world kilo speed record set with this lower unit was when it was on a 250 Yamato motor in 1992. Sean McKean did set kilo records in 350, 500 and 700 hydro classes but they were NOT with this lower unit and they were in the 1995 to 1998 time frame. The kilo lower unit still has some historical significance, albeit less than what I had originally indicated. I apologize for the error.

[David Weaver]

Well --------------- Greg McCreery is correct! It is a Rossi 350. Great Job.

In my opinion, when this engine showed-up at the 1998 O-350 World Championships at Cypress Garden, it represented a inflection point in the advancement of PRO racing in the US. With the exception of 2 competitive Yamato's, the GRM was the class of the field. Most US drivers were racing Konigs in 350 and scratching their heads afterwards. Never again, would a Konig seriously compete in 350 hydroplane except at an individual race or two. The 3-cylinder Rossi'd would dominate until the first 2-cylinder VRP's appeared.

Also, this race featured an APBA 125cc world championships. This was the first time that the Europeans had seen our single-cylinder class. Pete Hellsten had begun developing the Mac Minarelli engine. Eventually, the 125cc MAC would be produced by the factory. This event planted the seed for O-125 in Europe. We just saw how popular this class has become in Europe over the past 10 years.

We see few of these 3 cylinder GRM's at US races, but these engines remain very popular in Europe O-350 racing today.

DW

[Tomtall]

OK ---------------- This next engine has shown up on BRF before but there is a great deal of history posted on it so I thought I would add it to this thread. Can you fill us in on some of the story about this home brew engine?

Good Luck!

[Tomtall]

Well ----------- this engine was talked about in the 2007 AOMCI meet thread a year ago. Mark Sutter had the following to say about some replys about it.


Triple Carb 250 Opposed Twin

--------------------------------------------------------------------------------

Quote:
Originally Posted by Mark Suter
Eric, as far as I know, the 250 opposed is a Konig-built motor. Ed Thirlby told me it was raced by a guy named Harry Hardin out of Port Huron, MI. It has what appears to be a factory serial number on it (RA7080). The crankcase looks like it has been modified to mount 3 carbs in place of two but otherwise looks like it was designed and manufactured for the 250 application. Ed said it was not a very smooth running motor but it was very competitive. I bought it from a collector in Michigan who got it from Dale Robertson. Dale said it never was very competitive. With these two conflicting stories, I am not sure what the real story is on its performance. The pipes are fixed (not sliders).

I tracked down Harry Harden (who is from Linden, MI) and got the real story on this motor. Harry built it himself largely from available Konig parts in 1968 or 1969. Although he had ignition problems early on (hence the high speed miss that Ed Thirlby remembers), it was significantly faster than the Konig alternate firing twins at that time. Harry said he won a lot of races with that one-off motor... particularly after he changed coils and fixed the misfire issue. Apparently he got Deiter's attention because Deiter reportedly did follow up and build some opposed twin A motors. Although the serial number looks somewhat like a factory number and implies that it was a 1970 build, the number was "fabricated" by Harry only because NOA required that each motor be numbered.

[RichardKCMo]

Tom, great thread, though , i won't know many answers , allways liked the alkies , as before the 50s there was nothing else, i meant to say before mr C say what? but at any rate will read with int. Nothing like the sound of an old oppossed cyl. american motor turning unheard of rpms probly 7k
RichardKCMo
btw that's 1 reason i identify with the sound of d mercks, when i go to a race when i stop at the local store , i listen for the sound as i get iced up for the day, and then i have a sense of direction.

[Frank Volker]

I recall in one of the early races of the flathead engines, we went to a race in (I think) Constantine, MI. I believe this would have been about '64 or '65. We were especially interested in how the FA was going to compete, since most R&D began with this engine. I remember watching a guy testing this 2-cyl opposed A Konig. It "sounded" really slow, but during the A runabout competition, he had no problem accelerating away from everybody--including us. I believe he won every race he was in. We were stunned, to put it mildly. I don't think he ran hydro class, but I could be wrong. The name "Hardin" certainly rings a bell, but I'm certain it was before '68.

Frank