Merc 4 stroke vs 2 stroke comparison video.

[fishnfireman]

No doubt the R motors are different, especially the LU.
I don't understanding why the ProXS mtrs are not performing better than the 2 strokes they replaced on non performance hulls.
The new 8 cylinder has more displacement, lots more torque and they have lower gears, Word is the new torque master LU is also allowing for less propeller slip.
IMO-- if someone will spend the time and effort that River Rocket has they could be running the new mtr to it's full potential.
None of this came overnight, Geoff with help from Tim and Johnny have spent countless hours achieving these results and again I thank him for sharing.. I figure Mercury and Allison should put him on the payroll.
Its amazing how much better he has the 300R motor running than the 300XS.
I don't have the data to back it up. But seat of pants tells me my 250R will out pull my 300XS and quite possibly run as fast with a HEAVY load.
If you get time watch all of the videos he has put out.

[EuropeanAM]

Mike- there are plenty of folks running 250 ProXS Fourstroke models that perform at (or better than) the comparable ProXS Optimax model it replaced.

It's all in the setup... and taking the time to work with a variety of prop and setup options.

[fishnfireman]

Mike- there are plenty of folks running 250 ProXS Fourstroke models that perform at (or better than) the comparable ProXS Optimax model it replaced.

It's all in the setup... and taking the time to work with a variety of prop and setup options.

Thats good to hear..
All I'm seeing on here is how you need to go down in prop pitch.

[getfished]

I watched the video but it wasn't very helpful because either I read too slow or the data wasn't on the screen long enough. Sorry, seems like that might be kinda interesting.

[fishnfireman]

I watched the video but it wasn't very helpful because either I read too slow or the data wasn't on the screen long enough. Sorry, seems like that might be kinda interesting.

I kept my finger on the pause button.. stop it -- back it up-- take as long as you want..

[willy13]

don't care about the data... all that matters is that the new platform is so much sexier looking!!!

[Bassin Bob71]

don't care about the data... all that matters is that the new platform is so much sexier looking!!!

Well, there's the no compressor advantage along with the engine mounted oil tank which my 2012 is on its third as of a couple months ago. I'm getting a new boat with the 4 stroke 250 and I'm very much looking forward to it!

[EuropeanAM]

Thats good to hear..
All I'm seeing on here is how you need to go down in prop pitch.

Mike- We've talked about this repeatedly. I can explain it to you, but I can't understand it for you.

6 years ago a prop with 8% slip was a rare item. 10% was often accepted as "ok".

Today- with these engines running the same 1.75 Ratio, 6% is VERY common, sometimes even lower. Add to that the torque curve that is near-flat, and the engine continues to make HP right up to the top of it's RPM range with excellent torque (unlike the Opti which started falling off between 6000-6100 RPM's).

So a motor running the same ratio gearcase has roughly 4% lower slip, and needs to turn at least 200 more RPM's. 4% less slip is very close to what would happen with a 1.62 ratio gear, and now we need to turn 200 more RPM's (sometimes 400).

Your 300XS is different- as it's running a Sporty. While I've seen more efficient numbers from the new Sporty, it's often not a severe a prop-pitch change. Have to quit trying to apply information from your 300XS Sporty model to the hundreds of other V6 and V8 models.

[fishnfireman]

With all due respect Don you have totally missed my point.
And I am talking about my 250R

[EuropeanAM]

With all due respect Don you have totally missed my point.
And I am talking about my 250R

My apologies... went by your signature. That's also has a Sportmaster (very different from the gearcases discussed here), correct?

[fishnfireman]

My apologies... went by your signature.

Yes Sir...… Al put that up for me about 12 years ago. I've sent him several PM's to see if it can be updated.
I've tried to change only the make and year models and leave the rest--must be above my pay grade.

[getfished]

Got mine installed today. That's good. What's bad is I doubt I will be able to get it on the water anytime soon. I have some very overdue contractors coming to do some serious work at my house . I gotta hang pretty close. Sucks !

[fishnfireman]

Thats like cruel and unusual punishment..
I'm almost as bad.. the new boat is at lake Amistad 440 miles south of my house...and it's killing me to get back down there.. maybe late next week.