Water test on 115 HO etec

Workboating

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I just bought a 2019 115 Etec HO for my boat, I took off a 2007 115 Etec. The prop that came with the engine is a13 p. The prop off my old 115 Etec is a 15p. Will the HO make a difference, and does the computer need adjusted due to the change of prop. Or is it just like the older motors and just change the prop to get the correct WOT RPM"s
 

jlh3rd

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I'll go out on a limb and just say HP is HP.... 1960, 1980, 2007, 2019...doesn't matter.
Then I'd say what is the rpm @ WOT.
If you tune for more than rated HP, you change parameters but the bottom line #'s are what count for propping purposes.
See what the 15p does , go from there.
 

Workboating

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Thanks, kinda what I was thinking. I also didn't know that since its a fly by wire engine, if something need to be programed different when changing props.
 

jimmbo

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The computer is not going to adjust things for a different Pitch. It is simply feeding Fuel and adjusting the Spark, based on a expected Rpm Range under Load. That Load is provided by choosing a Prop that allows the engine to run WOT within that expected Rpm Range
 

Chris1956

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Both motors are the same generation. Not sure about gearcase ratio but would not expect it to change. You might check it out.

I would expect the props to swap over with the same performance.

Since you went to a 2"pitch less prop, I would expect about a 400RPM increase at WOT. If the old motor hit redline, I would expect your new motor and prop to exceed it.
 

Workboating

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Thanks Jimmbo.
I found that the spline on the engines are different. I will water test what I have and make adjustments. Thanks again.
 

Cynthia127

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The HO has a bit more power than the older models, so the difference in the prop (13p vs 15p) might be noticeable, especially under load, But best way to ensure you're hitting correct WOT RPMs is a water test.Supplement: As for the computer, calibration isn't usually needed, but check with a dealer just in case. ;P
 

racerone

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Is this the 3 cylinder 115 HP G2 model ?-----If it has different spline on the prop shaft , it might be a V-6 gearcase.
 

Workboating

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20240924_190132.jpg
I belive it's a 3 cylinder. I haven't t up.looked at the motor much, been working on getting it installed. I was able to do a start test last night. Motor started right up. The controls worked as they should. I didn't know how many options there were with this motor, until I started installing it. Crazy gage. It's hooked up to GPS, the fuel tank, smart trim. It shows so much, GPH fuel usage, trim degrees, engine temp, the motor has only 214 hours on it. So far it's traveled 1117 miles, used 209 gallons of gas. It's pretty cool as long as it all works.20240922_153453.jpg
 

Workboating

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The prop that's on it is a 13.5X17p I don't know how it will do, but when I run it this weekend, I'll make a note of it. Then order the correct prop. The ideal reminder is 5500, correct. I sae some on YouTube running 5200.
 

jimmbo

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It is Autumn, and if you prop it Now, or early Spring, you might discover it will lose some Power and Rpms come Summer. Something to keep in Mind.
 

jlh3rd

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yep, my best performance #'s are in early spring, cool air and water.
 

Workboating

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Ok, I did a test run today. Wot was 6200 rpm. I have a 13.25 x 17p on it. The boat was loaded as it will be used. 2.5 people and gear.
 

Workboating

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I looked, but couldn't find anything concrete.
From the what I see as available props, 13.5 x 19 or 21p. That's a lot that I have to drop it. I got scared when it reached 6200. It looked like it the speed platoed around 34, but I can't say for sure.
 

jlh3rd

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I'd be scared too, for my motor. You're 600 rpm above max, so I'd have to go with a 21P.
Propping can be ...expensive.
I'm ass-u-me ing the motor height is correct.
 
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