They Theirs wrote:I suppose there could be substance in that you’ve questioned BWYTodd report for the error in his propeller selection. Knowing he has the skill and ability to test first hand on the stock boats and the experimental craft, and provide his finding at no financial gain, (Surely your words, the larger cost more) providing what I suspected in computer controlled injection systems. The larger engine uses more fuel because it needs a longer injector dwell and fully opened throttle to produce more top end revolutions, (Remember Engines are Compressors) in claiming a whopping 22% power increase for an engine of the same weight and internal volume. Surely there could be error in results from first hand testing, and this fact cannot be overlooked, but coming from what has been a reliable source leaves little doubt in his candor.
hull, where do I start?
I never questioned Todd's qualifications, capability, or candor. I was merely pointing out that there was no determination on whether either motor (70 or 90) was propped correctly. hull, how many threads do we have discussing props. Getting the right prop means experimentation. I was just suggesting that maybe he put the 90 on there temporarily, with the same prop, to get some data. If so, then the data does not really deserve the pedestal you seem to want to put it on...
Furthermore, being one of the few dealers authorized to install a 70hp, he sure has a stake in play that combination up, versus other combinations... So I don't doubt anything he said. I just have questions about what he didn't say...
Finally, what would you expect the results to be if that 90 were underpropped? Like I said, I would expect exactly what he describes - little increased speed (it'd be hitting the rev limiter), increased fuel usage, and increased noise...
As for the warranty - Who here has had a warranty claim that in any way related to hull integrity and/or motor power/weight? No, I know there have been lots of cosmetic issues and some chain plate issues, but those aren't related to the interaction between hull and motor. Yeah, I know of one case where a poor installation of an oversized motor did damage the hull (when they hit a submerged object), but poor installation and hitting submerged objects could cause damage with a 9.9hp! There are just way too many people out there with 90hp motors and larger that have had no problems, for me to be too worried about warranty issues!!! Warranty is a dead argument!!!
I'm forced to take issue with the constant use of the word significantly. What one person might call significant is simply "in the noise" to another... Give me numbers and let me decide what's significant for me. If you don't have numbers, then all you have is opinion, and that's well and good ONLY if your trying to sell it as opinion...
They Theirs wrote:We have Todd & Randy Moon providing advice: "Sails better with smaller engine"
We know the larger engines are significantly larger in size, filling the motor well.
This is a red herring and has absolutely ZERO application to the discussion at hand! The 70hp and 90hp tohatsu are the exact same size and the exact same weight. Similarly, the 40/50/60 etecs are the exact same size and the exact same weight. Finally, the 75hp and 90hp etecs are the exact same size and the exact same weight. So, once you've started looking at any of those groups, I'm just urging the original poster to get the most HP...
They Theirs wrote:We don’t know if a different prop will produce an incremental gain
Surely, you jest? Not even you can be that much of an idiot! There is simply no way that a prop ideally suited for a 70hp motor on a 26M is also ideally suited to a 90hp motor on that same 26M, with the same gear ratios, etc. Here, the two "tested" motors used the same gear ratio. The simple fact is that any boat/motor combination will have a "sweet spot" prop. Any deviation from that "sweet spot" will cause SIGNIFICANT degradation of performance. For example, on my boat I can see as much as a 5 mph difference in using just the next pitched prop. (Hey, there's a number for you...)
Give the original poster your opinion. That's what they asked for. Better yet, tell them what you did and why. Tell them what you'd do differently, given your experience with your setup...
But, don't just cut and paste old suspect crap, add some color, and hold it out as scientific fact...