Mercury has added the 1.62 ratio as an available option when ordering a new 250R or 300R motor. Of course the original 1.75 lower will always be available too.
Which would be the preffered ratio to order for a new 300R motor? It will be attached to a new 21XRS.
I would go 1.62 if it were me.
Just spoke with Mercury Racing...about 1.62 ratio was told is not available in ordering 250R or 300R enginesOriginally Posted by Sleepy111
Nope. but they should a 1.61 coming soon.
Read this... Dan
http://www.bbcboards.net/showthread.php?t=948909
I saw that, that’s what made me ask over here. Talked to the dealer this morning who called Theresa about it so she called Mercury and they told her there is not a 1.62 option to order unlike Don spoke of. Somebody playing a late or early April fools prank.
And you heard that from who or where?
Recently was contacted by a member stating he had heard a 1.6 ratio was available. A brief scroll of listed model numbers (BY ME) showed a 1.62 Ratio Gearcase.
Please accept my apology- THIS WAS AN ERROR ON MY PART. The model I noted is actually the previous Optimax Model and NOT the new Fourstroke.
Absolutely No 1.62 ratio gearcase is available, and there does not appear to currently be any substantiated evidence that any will be available.
Last edited by EuropeanAM; 12-21-2018 at 03:24 PM.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Someone that knows lol..
I can't say but they know.
It maybe a while but they have one they have tested.
It would be far more cost effective IMO for Mercury to just raise the rev limiter on the 250R and 300R as they have done in years past with later models of the 300X and 205XS. First production ones had lower rev limiters than successive ones, especially with the 250XS/Sport XS
The rev limiter is set where it is because the torque curve drops off very quickly afterwards. Not to mention, they have to pay less in warranty replacements at lower rpms.
Is that a "torque curve" or a "Power ( HP) curve" that drops off? Is there a link to a Dyno reading? The R versions, already have "less warranty" and the XS/Sport XS also had reduced warranty so I can't imagine that being a consideration. Heck the old 260's and 300 drags came with NO warranty what so ever I'm told.
Torque and HP are (as you recall from your 250XS project) different items that relate where the “blade meets the water”.
Torque falling off at higher RPM’s is why that engine didn’t perform at 6700 as you originally thought- seems it landed right in the normal peak-curve for that series (5850-6150), more or less.
It’s often not nearly as simple as “let’s turn more
RPM’s”. ��
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Don, anyone who has tried has found that a 3L 250XS/Sport XS is VERY hard if not near impossible to get to make more top end speed/power than stock however, I was asking about the power curve on the new 250R and 300R. The previous poster stated the rev limiter was set on the new V8 250 motors where the torque curve drops off. Maybe you were trying to say that the new V8 motor also has a torque curve that drops off very quickly above it's existing rev limiter but I asked if it was both Torque and HP that dropped off very quickly and more importantly, if there was a link or a graph of the New V8's power curve from a Mercury Dyno sheet or anyone else' dyno shett of the new motor?
This all goes back to the original 250XS remark I made, the 03 and 04's had 5800 rev limiters, the models afterwards have 6300 limiters and in the case of the new V8's currently only offering 1.75 gear sets, raising the rev limiter IMO would be far easier for Merc to do than design and build a 1.62 R Sportsmaster. I assume, with the new motors, short stroke, and low compression, there is a LOT more room for both HP and RPM's increases? Many extremely go fast boats are struggling to find propellers with enough pitch and diameter with out having to get CNC huge $$$ dollar props. Diameter may still be an issue but with either a higher rev limiter or a 1.62 gear set, proping would be substantially easier from what I hear in my circles. I know it's sounds almost unbelievable but the 250R and 300R really seem to be a totally new type of animal.
Raising the rpm limiter will not help you that much. I run a 21XRD/300XS with the 1.4 DBR mod, and past 6200 rpm
there is really nothing there. I have never gotten close to the 7,000 rpm limiter because it runs out of torque and does
not pull any more past the stock limiter. I have both 1.62 and 1.75 SM lower units and have tried them both just to
see the difference. Day to day running the 1.75 gears are head and shoulders above the 1.62. Way better hole shot
and mid range is good to excellent, top end is not as fast but how many time can you run top end speeds. So turn all
the rpms you want to but if it's not pulling, you are wasting your time.
I was told by Mercury the new 300 V8 keeps pulling (making horsepower) all the way to the rev limiter where the old 300 Optimax motors stopped pulling around 5900-6000 well below the rev limiter.
Rex, thanks for the feedback on the DBR mod, what you relate is also my understanding.
Some how, I seem to be confusing people with what I'm asking? I know a 3 or 3.2 L has a peak HP and Torque curve that runs out above 6200 VERY well, but what I'm asking is that earlier in this thread, it was stated that the new V8 motors also have a "torque curve" that quickly drops off over 6000 Rpm. I asked if someone had a link, graph etc of an actual Dyno pull that shows that? Is there a dyno chart of a 4.6 L V8 Mercury out there that shows both the torque and HP curve?
I hope this clears things up?
Paul, thanks! Some how everyone was misinterpreting what I was asking. Paul, so based on what you have been told, raising the rev limiter on the NEW V8 Mercury's would NOT push things above the peak HP and Torque curves? I had suggested that, like the original 250XS in the 03 and 04 years the Rev limiter was set several hundred RPM's ( I believe it was 5800 RPM? ) bellow the 05 and up motors which then set the Rev limiter at 6300 RPM. I questioned and suggested that the Mercury could much easier address the motors proping issues on very fast boats by just merely raising the rev limiter like they had done with the 3L XS motors, than having to design a new 1.62R version Sportmaster.
Do you agree?
Thanks and Happy New Year :-)
Raising the rev limiter on the new 300 hp V8 motor should make more horsepower since it’s still pulling at 6400 rpms. If the motor makes more horsepower power it can’t be sold as a 300 HP motor. Changing the gear ratio won’t make any more horsepower, it will only make the motor easier to prop on lighter boats. Mercury knows what they are doing and what the next steps need to be.
Paul, that's an interesting point about "it can't be sold as a 300 Hp" You know much better than I do but how did Mercury address, the 300 Drag, the 300 Pro max and the 300X and the 300XS, they are all "300 Hp" motors but clearly on the same dyno at the same time they would produce different HP? I'm really not sure "where" HP measurements are taken when motors are rated? I assume it's the "peak" HP and then the 10% +/- is allowed for?
I'm confident Mercuy knows what they are doing, it seems though initial new motors are conservatively RPM limited? The 250XS being a great example but the 300X was also like that and you would know a lot more than I but the 2.5 race motors had some really wide RPM ranges depending on year and model of motor built correct ?
PS Happy New Year and I hope all is well
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