HPDI reliability and improvements over 4-Strokes

[Instigator]

Not sure on the 10% rule but that’s what I had always heard.

Back in the old days, OMC’s said on their ID tag, “OBC” rated horsepower.

Outboard

Boating

Club (of America)

Merc didn’t do this and stated whatever they wanted.

That was the begging of the horsepower wars.

They we’re advertising 18 hp, 20 cu in motors as 10 hp against OMC’s 15 cu in 10 hp motors.

To the OP’s orig question, the HPDI Yammi 2 strokes didn’t have a very good reputation and I don’t think production lasted very long.

I liked the design but had no first hand experience w/them.

A few yrs back a saw a bass boat at a ramp w/one and I quizzed the owner.

He had recently bought it and was a rebuild.

He had also spent a fair amount of $$ on it to keep it up.

Said it was making the new motors (Merc 4 strokes) look good to him.

I think you could apply his story/experience to every 2 stroke I’ve seen.

W/the level of tune required for a DI 2 stroke to pass the sniffer tests, they are so lean, and close to melt down, if they even hick up (water in fuel, too much wheel, basser abuse) I wouldn’t expect one to live.

On the big E-Tec’s on the (highly strung) bassers, it looks like 2 - 300 hrs of life is common.
(similar or a bit more than the Opti’s)

In a lesser stressed environment, I’m seeing/hearing 5 - 10 times that.

Just read of an owner winterizing his 225 e-etc (I think in Fla) and it had 1700 hrs and was orig
and have seen many for sale with 2000 hrs +.

[Greg G]

The 200XS Gen 2 did make 238hp, I was confusing it with a dyno print of one of my Promax 225s which made 242.

The 238 hp is at the prop shaft and at the start of production anyone who could put down 50% could buy one, not just race teams.

[abdrews013]

Sorry to the OP for this going so far off the rails. But I'm interested in this subject. How did it make 238 legally? I found a source for the 10% rule. From ICOMIA 28-83.

7 Manufacturing tolerance

The corrected power at rated speed of any individual marine propulsion engine or propulsion system must not deviate more than ±10% or 0.45kW, whichever is greater, from its declared power, except that for governed engines or systems of more than 100kW [134-HP] the tolerance shall be ±5%.

The next question is whether that's law or a suggestion.

https://continuouswave.com/whaler/re...OMIA28-83.html

[David]

The EPA does test 2 strokes under load. I'm not informed enough to really understand the duty cycle in the testing. Maybe Hellbents can explain it. Lean at WOT is going to blow up a lot of motors, not just 2 strokes. But perhaps more likely with 2 strokes.



I got this 200XS dyno curve here on SnF a couple of years ago. It clearly shows 'powerhead' and 238 HP. Gen 1 or Gen 2? SAE corrected for air pressure, temperature, humidity?



To me, the AFX is not really equivalent to a 200XS ROS. There was a small gearcase race motor that used the same powerhead as the 200XS. That would be the comparable motor.

[Greg G]

I got this 200XS dyno curve here on SnF a couple of years ago. It clearly shows 'powerhead' and 238 HP. Gen 1 or Gen 2? SAE corrected for air pressure, temperature, humidity?



To me, the AFX is not really equivalent to a 200XS ROS. There was a small gearcase race motor that used the same powerhead as the 200XS. That would be the comparable motor.

I am the one who posted that dyno curve David. A lot of bad info here on the thread. First, the 238hp was at the prop shaft as stated by the guy running the dyno. Second, it is a 200XS Gen 2 which began with the 2.5 XS that was only built for 2005. When we dyno'd my Promax 225 there was a Gen 1 next up. It dyno'd 211hp at the prop. The Gen 1 was weak which led to the 2.5XS powerhead and then on to the 200XS ROS Gen 2 which was stout at 238hp. Last thing is go out and look at the tag on your motor and report back RPM and weight. Merc has been lying about weight for decades.

I have comments on the 200R V6 but I'm crashing after to much trick or treat candy down herre with the kids!

The 200R is a trick, not a treat. More in the next couple days

[David]

238 HP could conceivably be in the 10% window, if the 238 was recorded at exceptionally good atmospheric corrections. Gross dyno numbers are normally corrected for air temperature, pressure, and humidity. Having said that, down 18 to 220 seems like a big correction.

Did I get these 225 Promax dyno print outs from one of your posts as well?



Seat of the pants, there is not a big difference in mid range and top end between the 225 Promax that I used to have and the 200XS that I have now. The Promax was much stronger off idle. (1) It idled twice as fast (2) 1.87 gears vs 1.87

It's possible that the 200R could have more power than the 200XS and more mid/low end torque. I don't know if Merc could stay in the 10% range and have much more power, but as noted above, 10% doesn't seem to be a legal requirement. But the 200XS might still be better for my Allison. Lighter, short shaft, and a 4.75" sportmaster.

[abdrews013]

The only problem is this "...except that for governed engines or systems of more than 100kW [134-HP] the tolerance shall be ±5%." I'm thinking more and more that it's a guideline, not a law.

[David - WI]

Three groups care... stock-class racers, fishing tournaments, and insurance companies; everybody else would be happy getting more power than advertised.

[Instigator]

One problem is, and always has been, brand X sells 225’s that are 250’s w/225 stickers.

Brand Y sells 225’s that are 225’s.

Guess which brand anyone performance oriented buys?

I do think in the last 20 yrs they have gotten closer though.

I know for a fact an OMC, carbed 225 HO runs right beside or just ahead of a 225 Pro Max.

From #’s I have seen, both camps are full on at + 10%.

Three groups care... stock-class racers, fishing tournaments, and insurance companies; everybody else would be happy getting more power than advertised.

[David - WI]

I agree, but nobody complains about getting more than they paid for.

[abdrews013]

I agree, but nobody complains about getting more than they paid for.

Unless it's weight, like the four strokes!

[Greg G]

238 HP could conceivably be in the 10% window, if the 238 was recorded at exceptionally good atmospheric corrections. Gross dyno numbers are normally corrected for air temperature, pressure, and humidity. Having said that, down 18 to 220 seems like a big correction.

Did I get these 225 Promax dyno print outs from one of your posts as well?



Seat of the pants, there is not a big difference in mid range and top end between the 225 Promax that I used to have and the 200XS that I have now. The Promax was much stronger off idle. (1) It idled twice as fast (2) 1.87 gears vs 1.87

It's possible that the 200R could have more power than the 200XS and more mid/low end torque. I don't know if Merc could stay in the 10% range and have much more power, but as noted above, 10% doesn't seem to be a legal requirement. But the 200XS might still be better for my Allison. Lighter, short shaft, and a 4.75" sportmaster.

Yes those are my Promax 225 dyno prints. The exact same shop and dyno ran my 280 and it came in at 281hp. A few years later after Lee retired I went to Marty and they rebuilt my 225X. It was one of the last rebuilds Diamond did before they retired and sold the shop. I asked him if he would do me a big favor and break it in on the water which he kindly said ok. He then put the 225X on his dyno after break in and it pulled 247hp. Obviously that was a full rebuild with 12 hours of break in BUT interesting against the 200XS 2.5 ROS.

[Greg G]

More to follow on the 200R BUT as a sidebar to the OP on the Yamaha HPDI's. I have had several and generally the 225hp which was the 2.6L was better. The 3.3L 250 and 300 had a couple of issues with locater pins. The key for both motors is proper maintenance of the many filters the HPDI runs. If you can get non ethanol 87 that solves a ton of problems but I can't get that in our area. I have a spare 250 Vmax HPDi that I would sell AND there is a mint low hour 225 Vmax 2.6 for sale which is rare.

[Greg G]

It's possible that the 200R could have more power than the 200XS and more mid/low end torque. I don't know if Merc could stay in the 10% range and have much more power, but as noted above, 10% doesn't seem to be a legal requirement. But the 200XS might still be better for my Allison. Lighter, short shaft, and a 4.75" sportmaster.

I don't have a dog in the fight and good that Merc at least put a V6 R model out BUT why do they have a 225hp V6 already and chose not to make the R a 225? Annoying and stupid IMO as you would have had a torque monster with 250hp burning 87 with warranty.

[Greg G]

As far as the 200R weight with a Sporty would have to put it on the digital scale to get a real weight like Randy did with the 300R at 561 lbs. Mercury has been lying on motor weights for decades.