When did Mercury Detune the ProXS?

[clayc]

I've read several comments where Mercury detuned the ProXS. Is this true and When did this occur? What was the actual hp on a particular engine prior to detune? Why was it done? Was it detuned thru computer?

[jethro1]

If you read it on the inner web it must be true. Nothing can be published on the inner web unless it is correct. I read this on the inner web.

It is true regarding the Pro XS. They detuned it to reduce emissions so that the two stroke configuration will not be phased out by the EPA as soon as it otherwise would have been. Pro XS is now on its way out. Heading out the door. Parts will stop being available so that the motor will have to be scrapped sooner rather than later.

HP reduction happened the first of this year. A 250 was outputting about 265 HP at the propeller. It is now down to about 240 HP.

It was all in the ECM/ECU/EMM.

[Savage]

I've read several comments where Mercury detuned the ProXS. Is this true and When did this occur? What was the actual hp on a particular engine prior to detune? Why was it done? Was it detuned thru computer?

Is your question pertaining to your 2013 200 HP motor?

Changing ONLY the computer on ANY Horse Power ProXS motor will NOT increase the HP......PERIOD!!!

[fishfarm]

Got to love all the EPA standards for motor companys. Like mine they run on 87 octane as well but still loving my newer pro xs. That motor pushes my ranger 520 to 74 and have seen almost 76 out of her which is damn good for a 17 year old heavy Ranger

[FastCat04]

"HP reduction happened the first of this year. A 250 was outputting about 265 HP at the propeller. It is now down to about 240 HP." from Jethro1..

Savage or Don...is that true? I just ordered a new BassCat Eyra with a 250 ProXS...hope it is just as strong as they have been for last few years !!!

[MengRanger]

If I remember correctly, the year that the Gen 2 TM lower unit came out. This was to offset some of the HP reduction. Have not heard of any changes since then, but Don will definitely have more detailed info.

[06 SB]

"HP reduction happened the first of this year. A 250 was outputting about 265 HP at the propeller. It is now down to about 240 HP." from Jethro1..

Savage or Don...is that true? I just ordered a new BassCat Eyra with a 250 ProXS...hope it is just as strong as they have been for last few years !!!

Here are Don's words from a while back about this:

Guys:

First- Mercury DOESN'T USE YEAR MODELS (and hasn't for a NUMBER of years). That is (as earlier stated) why it's so critical to provide an engine serial number - the serial number is the ONLY accurate identifier for a particular engine.

Mercury's PRODUCTION years run July 1 to June 30th. However, that doesn't mean changes only occur on July 1st (they can take place at any time throughout the year).

There were changes to the 250 ProXS DURING 2013 production, which affected BOTH 250 ProXS models. These changes bring the engine into compliance with the new EPA "NTE" (Not to Exceed) emissions standards.

Changes DID include more than just a new gearcase and a calibration/PCM change.

The resulting horsepower LOSS averaged approximately 5-6hp at the PropShaft. Models utilizing the newer Gen-2 Gearcase will actually outperform previous (Gen-1) models, PROVIDED they are appropriately set up.

The new Gen 2 Torquemaster was designed to recoup the lost hp. You picked the right motor IMO.

[FastCat04]

06 SB......I hope that's still a valid statement !!! But it would be my luck that I order a new boat with a 250 and it be the 'detune' year :( Hope that Jethro1 just had old information !!!

[06 SB]

That is usually my luck too. I am going to continue to believe in Don until HE says something else has changed. My new-to-me 2016 Cougar has a 250 ProXS and is a beast compared to the P2/200ProXS!

[FastCat04]

Amen !!!! Don & Savage are the 'Mercury Gods' and I believe and trust in what they say.

[Rich Z]

We have not heard of any recent changes to any new opti motors. We have noticed that around 2011 or 2012 with the latest generation of opti fuel injectors that they are leaner by approximately 2-3%. This could explain the power reduction as it did happen during that time frame and a year or so later the new aka wing master was introduced to compensate for the reduction.

[nightbasser]

They probably took some timing out as well

[EuropeanAM]

If you read it on the inner web it must be true. Nothing can be published on the inner web unless it is correct. I read this on the inner web.

It is true regarding the Pro XS. They detuned it to reduce emissions so that the two stroke configuration will not be phased out by the EPA as soon as it otherwise would have been. Pro XS is now on its way out. Heading out the door. Parts will stop being available so that the motor will have to be scrapped sooner rather than later.

HP reduction happened the first of this year. A 250 was outputting about 265 HP at the propeller. It is now down to about 240 HP.

It was all in the ECM/ECU/EMM.

Well... not everything you read on the interweb is true.

This "detune" was part of the NTE (Not To Exceed) Emissions Standard that was prepared for (changes made for) in 2012. The loss was NOT in the PCM (though there was a new, complaint calibration), there is a hard-part detune at play.

That being said- the engines still put out well north of the 250 mark once broken in. Actual loss (on a properly running engine) was close to 6 PSHP. And the gains from the Gen-2 Gearcase more than compensate for that.

[J Risco]

Well... not everything you read on the interweb is true.

This "detune" was part of the NTE (Not To Exceed) Emissions Standard that was prepared for (changes made for) in 2012. The loss was NOT in the PCM (though there was a new, complaint calibration), there is a hard-part detune at play.

That being said- the engines still put out well north of the 250 mark once broken in. Actual loss (on a properly running engine) was close to 6 PSHP. And the gains from the Gen-2 Gearcase more than compensate for that.

The question begging to be asked here is WHICH hard part...

Im sure lots of guys would like to swap back to the 'better' one!

[EuropeanAM]

Not really feasible (and certainly not legal).

Hard parts included the throttle cam, exhaust tuner, PCM (specifically the calibration).

[J Risco]

Not really feasible (and certainly not legal).

Hard parts included the throttle cam, exhaust tuner, PCM (specifically the calibration).

I hear ya, but hot rodding engines is somehow embedded into the American way of life haha, someone will always be looking for more, legal or not.

I figured the exhaust tuner might be a part of that puzzle. If someone wasnt worried about legalities, warranties, or safety they could run all the 'best' parts, turn up some pressures, massage some other stuff, run a wingmaster and have a heck of a strong Opti!!! Not for me, but Im sure there is someone out there that wants to... or maybe just buy an 04-05 250xs

[EuropeanAM]

...or maybe just buy an 04-05 250xs

There ya go! I've even got a good project candidate sitting right outside my window ('05 production).

[EuropeanAM]

Savage is wrong! You can change the horsepower on a Mercury 2 stroke by changing the computer only.
Richard AKA Kllr bee

Sorry Richard- that is INCORRECT.

2-Stroke Optimax engines (especially the 3L models) have DIFFERENT EXHAUST PORTING for most HP series. Cylinder heads are ALSO different.

You cannot simply change the PCM and turn the engine into something else.

And there's a whole lot more to "Factory Tuned" than just the PCM. SOME of the common differences include Pistons, Heads, Block, Rails, Direct Injectors, Ignition, Plugs, Air/Fuel Pressures, Air Compressor, Reed plate, Reed Blocks, Reed type, Crankshaft and PCM (which is certainly not an exhaustive list).

[bass.man65]

So you are saying if you had a 200 Pro XS and put a 250 Pro XS computer on it you would see absolutely no performance gain whatsoever?
Richard aka Kllr bee

Actually would run worse so your answer would be no performance gain whatsoever. The Pro XS is not a SHO

[EuropeanAM]

So you are saying if you had a 200 Pro XS and put a 250 Pro XS computer on it you would see absolutely no performance gain whatsoever?
Richard aka Kllr bee

You would have an engine that idled very poorly (if at all) and chugged down an inordinate amount of fuel. Those two engines have different sleeves, heads, pistons, air compressors (at a minimum)- and depending on the serial number of the 200, may have a completely different ignition and fuel system.

For a better understanding, look up the companies that make sleeves for these engines.

GODFATHER: WHY did you decide to post a toobe video in a thread that has been dead since 2017? There was no purpose or benefit to the original poster.