Merc 650xs

[Popa Sam]

I ran across this in some old papers and thought it may answer some questions that I've heard about these motors. Mainly when they were introduced.

[peterse90]

The 650XS was legal for FE and SE classes here in Canada right from the start.
A few showed up in 1975 and by 1977 there were quite a few.
I had mine in 1978 and 1979 on a Seebold SE hull.
They were still being used and still very competitive right into the mid/late 80's against the OMC's. That's why FE/SE were such great classes to race in here in Canada because we had Merc VS. OMC racing.
I believe the 650XS was a legal engine everywhere but the US.
The Merc 650X (the MOD 50 version) I think started in 1976.

[Mark75H]

I thought the XS was approved by APBA as a regular FE/SE motor ... 250 per year, sold thru regular dealers and advertised in the regular catalog.

[peterse90]

Quite a few American drivers use to compete in our CBF races here in Canada, not one had a 650 XS.
I remember the SE class in St. Louis in 1980, about 20 boats and not one Merc.
I think by 1975 Merc had pretty much handed FE/SE to OMC in the US.

If I remember correctly any joint sanctioned CBF / APBA races that were held in the US we were not allowed with our 650 XS

[Mark75H]

Yeah, if the 650XS was sold in 75 and was not in the 75 catalog, APBA might not have approved it until 76 when it was in the main catalog. That would explain it both ways.

The XS had more success in Europe than North America, even that ended as the OMC Mod 50 motors evolved. In the kneel down modified division, one of our bench marks is the power head had to have once been approved as an OPC stock motor. The 650XS is legal under that definition in mod. The X motors were run under APBA OPC mod rules and OE rules and didn't have to be approved, so the 650X and 700X are definitely out ... even if enough of them had been made.

[peterse90]

The XS had more success in Europe than North America, .

The XS had GREAT success here in Canada, and was very competitive for many years.

[Popa Sam]

I don't think the 650xs was ever approved as a SE/FE motor by APBA. I don't remember why, maybe because it was advertised as a high performance racing motor. I know during that period there were a few guys running Mercs but were running the 650E. I'm sure if the xs was legal they would have been running it.

[Mark75H]

It wasn't advertised as a racing motor and the minimum quantity was met each year. It was in the regular fishing catalog with the 1500XS that was raced in FJ and SJ.

Maybe it was never approved, but Merc had jumped thru all the hoops. Possibly politics in APBA ... not the first time or last time.

[peterse90]

Good point about the 1500XS being legal, but I think Merc made plenty of 1500XS's that found there way onto race and pleasure boats.
I have a feeling the 650XS was very limited in supply and possibly they didn't make enough of them to meet the APBA rule OR as you say there was some politics that FE/SE became OMC's and SST120 became Merc's.
I raced the 650E in 1974 and then the 650XS in 1978 & 1979. They were as different as night & day. The XS had to burn aviation fuel at 18:1, could rev to almost 8000 and sounded pretty much like a MOD 50 motor.

[Mark75H]

They made 250 per year per APBA rules for a stock production motor.

Like I said, Merc jumped thru all the hoops for this motor.

[88workcar]

Just in reading it seems that the comparable evenrude would be the 60sst, when did it come out and how did it fair against the 650xs?

[Mark75H]

Not raced in the same era. Different classes, different worlds

[Roy Hodges]

[QUOTE=88workcar;98321]Just in reading it seems that the comparable evenrude would be the 60sst, when did it come out and how did it fair against the 650xs?................................
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the factory RATING on the 650 XS was 90 horsepower.I once had a brochure on it.Merc did NOT build enough of them to be legal in the Sport E or Family E classes. It was basically 1/2 of a Mercury T-2X powerhead.

[stinger]

There were a good number of 650xs running here in australia from 1976 on.Also 650x and 700x.These motors were basically a twister 11X cut in half. The 650xs was used on both v bottom and tunnel boats.Rated flywheel hp was approx 90hp.The 650xs in competition here, was performance wise ,about equal to omc 75 stinger and hustler short shaft models,maximum flywheel rated at 80hp. The omc model FT19s came here in 1977 with a flywheel rating of 110hp, these competition models were allowed to run in stock class?The omc FT19s was far superior to the 650xs. The 1500xs and 85xs models here were basically stock although slightly tuned,the 1500 at 155hp and the 85 at 90hp.

[Mark75H]

In the US we were never told the 850XS was anything other than 85 hp and OMC never revealed the hp of their race motors.

Do you know what would be different to make an 850XS 90 hp instead of the regular 85 hp?

[Popa Sam]

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.Merc did NOT build enough of them to be legal in the Sport E or Family E classes. It was basically 1/2 of a Mercury T-2X powerhead.[/QUOTE]


Not enough built was what I recalled as well. Thought maybe was not true with the response here.

[stinger]

Gday Sam .Firstly i would like to say how awesome this site is.The things ive read and learned is amazing. As i remember, the 850XS from the stock was 3 deg W.O.T advance and 3 thou larger main jet to acheive the 90hp quoted . Wiith regard to the omc motors,when they were purchased new,either Australian or Belgium models, were supplied with a spec sheet detailing outputs.Independant Dyno tests varified any queries.

[Mark75H]

I know its been a long time, but if anyone could come up with some of that documentation for show and tell, it would be awesome.

[fyremanbill]

Speaking of the 850xs, what are they worth? There's a guy in my area trying to sell one in so-so cond for $800.