prop for 90 etec

[SENSEI]

I have decided to replace the 90 Honda with a new 90 Etec
I am curious as to what prop you etec owners are using. I have a 95 angler so the weight will be less than a cruiser but I need some starting point for my boat.

 

[island andy]

Roger, I just went thru this last summer with my 2007 Cruiser.
I followed the process described in the Verado owners group posting by Glenn on "propping correctly and how to test props" . I got that lead from a thread on this forum last summer on propping. Propping is the same process independent of brand of motor, as I imagine you know.
For me: freshwater, usual load, 13.75" dia X 13" pitch, cupped [by local prop shop], gave me 5100 rpm WOT. The particular prop I use is a Solas Amita 3 blade. As I recall, speed was about 31 mph, but I was not concerned about that. Speed is what it is if rpm's are in range.
I support your decision to go with an Etec. Lots of good motors out there [and opinions], but I am a two stroke fan and the Etec is fine with me.
Let us know what you decide on!
andy

 

[SENSEI]

thanks Andrew
it will help me to get close.
On the original Sensei (1983) I had the 90 Ficht which was the precursor to the Etec and I absolutely loved that engine. it was great for trolling and all in between. I carried a 9.9 tohatsu 4 stroke that never got used because the ficht trolled so well.

 

[thataway]

Roger, I just went thru this last summer with my 2007 Cruiser.
I followed the process described in the Verado owners group posting by Glenn on "propping correctly and how to test props" . I got that lead from a thread on this forum last summer on propping. Propping is the same process independent of brand of motor, as I imagine you know.
For me: freshwater, usual load, 13.75" dia X 13" pitch, cupped [by local prop shop], gave me 5100 rpm WOT. The particular prop I use is a Solas Amita 3 blade. As I recall, speed was about 31 mph, but I was not concerned about that. Speed is what it is if rpm's are in range.
...
andy

Sorry to disagree with you on the bold part.

The different outboards even in the 90 hp range have different gear ratios.

They vary from the Etec 90 with a 20" shaft at 2;00;1, 25" shaft 2.22:1, Honda 2.20:1, Yamaha 2.27;1, Merc 2.33;1, up to Suzuki at 2:59:1. So the prop you use will depend on what gear ratio your specific outboard uses. The correct prop is determined by the RPM Wide open throttle. vs the speed. Generally I like to hit mid range RPM. depending on load. If I am testing with the boat light, then I want the WOT RPM to be at the upper limits--when a bit loaded WOT RPM will drop.

Also you want to choose a prop for the load you will normally have and the altitude you are running at. Because of HP loss in some engines, you may drop 2" of pitch for every 3500 or so feet of elevation gain.

So a 13" pitch may be perfect for an E Etc, a 15" for a Honda, and a 18" for a Suzuki. Each boater should do the tests on his or her boat, with the load and altitude that they normally run at.

 

[island andy]

Thataway,
My apologies for my failure to communicate well.
i was trying to say that the PROCESS of propping is the same across motor types and that includes lower unit gear ratios. The article I was referring to suggests that the motor be at the proper transom height [and how to determine that], then run with the prop in question and the motor gradually trimmed until it ventilates. The rpm's at the point just before ventilation occurs is the WOT rpm for that prop with that load in that solution of salt and water at that elevation. I think I included the relevant conditions for my propping foray except the implied one of elevation. In the Great Lakes, we are about 700 ft above sea level.
I was trying to suggest going to the literature, or at least a relevant review article for more info., and suggested a reference which resonated with me.
Apologies,
andy

 

[jennykatz]

We had a 1999 cruiser and had the older 90 hp Suzuki(2.0L)2006 we had a 14 by 18 pitch and the boat would hit 35-36 mph WOT what an awesome motor .. I have friends that had a Honda and if it reached 30 mph that was a good day .We usually ran it at 20 mph for a nice relaxed run .The lower unit gear case and what displacement you have give the prop shop an idea of what prop to use .
Go to a good prop shop and try different props for your engine and boat combo .

 

[thataway]

Andy,
Thanks for clarifying: Here is the link to that helpful article.

Engine height is very important. Unfortunately many owners don't take the time and trouble to move the engine up or down. Lacking that, I like to trim the motor so that you reach max RPM, with the boats normal running attitude.

I suggest that the tabs be utilized to give the normal or best running angle, as being another factor.

Getting the "perfect" prop is difficult--because our boats vary so much depending on load--which is extremely important in C Dory.

I like to see my RPM at the top end of the manufacturer's wide open throttle suggested range, not the bottom.