So your 60 is the top of that block class: 40/50/60. Doesn’t that mean you won’t get those big numbers? IDK. I’ve just been reading like everyone else. M
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I can get to 75hp, like the rest. Diminishing returns for sure, but it should be enough to make substantial improvements.
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I think what you’re doing will give you excellent information, assuming it works the way you expect, it will give you better performance.
Here is what you can’t do reference performance data. (I have pretty extensive background in operational testing of machines, our goal was to find find optimum performance and meet requirements, most of this had to do with different systems, but the ops analysis process is the same, so I’ll expand a little on this). What you can’t get is long term performance assessment, most large companies want an engine (in this case zuk 60) that will last “x” parameters, most of it reflected in their warranties, and liabilities requirements.
So the testing is done to find it’s time between failure at different levels of performance, since the advent of Digital Engine Controls, they optimize the parameters for the commercial product you have. They know exactly how to make it tune it leaner/tweaks and generate higher BHP. So they accelerate a statistical relevant amount of engines to obtain that data, from there they derive what you see in the market. They will never share that data, unless it’s in the contract for the organization that wants the tool.
I am oversimplifying the process but you get the idea, there is no doubt you will have a better engine in terms of BHP which will translate to better HP at the prop shaft.
What you don’t know is whether your TBF is higher, it may not depending on luck and hopefully not running it at temps and harmonics that will create a problem sooner, you just don’t know that unless you have the resources to accelerate the life of a test engine platform and even then you need at least 8 engines to adequately evaluate statistical performance evaluations of what you are doing to the engine etc.
Now an outboard is not going to really affect you if it quits, but an aircraft engine could, different problem but evaluations are the same.
I’m in the side of do it, it should work, but don’t be surprised if you have an engine that fails sooner than it should.
Let us know how it goes!
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Great info.
I am trusting in the fact that these companies have been around for over 15 years. I have seen quite a lot of feedback on 4000+ hour tuned outboards.
The pending Tohatsu tune is a good example. OEFI has sunk big money and three years into it. They do lots of heavy testing including taking motors to intentional failure to find real limits.
I’m not blind to the risks, but I do feel like they are pretty low. And to your point, if it fails 
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I like your plan. Seems very thorough given the resources. I do suggest run each test maybe 3 times to confirm you get repeatability, record each run. The confidence factor increases when its reasonably repeatable ( less standard deviation). This is all shade tree testing anyway, meaning what Loogie is discussing is out of your capability, but he is spot on. A manufacturer would get into statistical modeling, etc. Been there done that, have see organizations and engineers go into analysis paralysis with this type stuff. Then Smokey Yunick steps in and tells the engineers they are full of ■■■■, yes that can be done, I have been doing it for 5 years. 
On the long term question, just report back on the same thread over time, giving your hours run since the flash, and any issues experienced.
I can geek out on this kinda stuff. 
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BTW, I bought a Yamaha 200SHO for my Bay Boat for some of the reasons you stated. The price difference wasnt substantially more than a 4 cylinder Yamaha or Suzuki, I got 6 cylinders for more torque (I replaced that 2 stroke I mentioned before)…..and….. I can tune it when I want. ( knowing its a detuned product)
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Looks like Bayou Meto. Guys die every year there. Its crazy. I hunt about 15 mile away from there. We dont go there 
FYI: and Evinrude/Johnson 9.9 is the same engine as the 15hp. They just choked it down with a smaller throat in the carb. 15hp carbs sell for a couple hundred on ebay. That engine is very tunable.
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When the Tohatsu tune comes out I will probably get it. Can’t leave good enough alone and I have enough gas capacity for a little extra burn.
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They advertise 15% fuel burn improvements at midrange.
I ordered the NEMA kit. It will probably take me a few weeks to make the time for all of this.
Flash your Suk and report back after 100 hrs.
Exactly Loogie. Second guessing teams of corporate engineers is not a good idea. But if you have deep pockets and engine replacement is no big deal go for it Renegade. Just experimenting
As an engineer in the automotive market I can say that I’m certainly fine second guessing corporate engineers. .
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Perhaps you missed my post from the discussion with the owner of OEFI. it’s a few posts up.
This is not a matter of second guessing engineers. It’s an exercise in tightening up margins for bad fuel, intentionally designed by the engineers for the broader global market.
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Since I’ve got a Jet I’m not hitting anywhere near rev limiter. I think my WOT is around 54-5500. So if I could get another 2-300rpm or so I think that’ll get me another 2mph with a little quicker launch. Well worth the money and I’d feel fine about cruising at 5750 for long periods of time since it’s well below the limiter.
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I look forward to the testing results.
I’ve done a little research on this as well for my Suzuki 90. Suzuki actually sells a 100 hp engine overseas that is the same displacement as the 75/90 engine family. The rpm ratings for the 75 is 5000-6000 rpm, 90 is 5300-6300, and 100 is 5700-6300.
So I have thought about buying a factory Suzuki ecu from overseas for the 100 or getting a tune from outboard efi, but theirs much like factory pics up 10 hp. I will likely look into these once my motor is out of warranty. If I could pickup a couple more mph or spin more prop such as a four blade at a similar mph I would be all in.
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So the factory-tuned ECM has the timing retarded for low-octane fuel and OEFI is basically just advancing the timing curve based on higher-octane fuel. If you run the tune-specified fuel and you don’t hear knocking and your engine temps are in a safe range, your motor isn’t being damaged.
60 horsepower at 6300 RPM (Suzuki factory numbers) means 50.02 ft-lbs of torque at 6300 rpms
75 horsepower at 6600 RPM (OEFI) means 59.68 ft-lbs of torque at 6600 rpms. Almost 20% gain!
If their dyno shows a roughly 20% higher torque curve throughout the RPM range, that will be a nice usable gain. If its just a big power hit at the last 1000 rpms, it probably won’t be worth it. A dyno would be nice to see.
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Following this myself. I have a Tohatsu 50 hp just out of warranty that I am interested in bumping to a 60. One path is an ECU swap, but I will wait until OEFI releases their solution.
But that leads me to a question about the Tohatsu mod….
If the T50 is the same block as the T60, I do not understand why the 50 only gains to a 60 and the 60 jumps to 75 hp.
If it is the same block, why wouldn’t the 50 also be able to each the 75 hp numbers just lke the 60 when tuned?
Depending on what I learn, I could take a 60 ECU and then mod to get a 75 from the tune. But I don’t see why that cannot happen with only the tune. Once they release the official tune, I’ll inquire.
You will get 75 without an ECU swap
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He has dynos on the site. I have seen the Df60 but can’t find it right now, just the DF40.
On that motor, the torque peak is 4750 but it is quite a bit higher than the horsepower. It inverts around 5700. It’s not 20% throughout but it builds beyond 20% up to peak torque
The Yamaha f70 is essentially parallel until the top of the rpm range.
