# Yamaha 115 4 Stroke outboard advice



## MyTimeToPlay! (Feb 11, 2011)

I have a 17 ft Cape Horn with a Yamaha 115 4 stroke. It gets up and plains out pretty quickly. I was wondering if some one could tell me what the most efficent (easy on the engine and gas efficency) rpm's to run at is? Also, with the throttle all the way to the stops its at about 49K. Is it hard/bad on the motor to run it open at those rpms? I've been told this motor is "bullet proof" but don't want to tear it up.
Last question, I've been learning a lot of self maintenance by watching youtube videos. All the basic maintenance seems pretty easy. When it comes to taking the prop off to grease the shaft, is the amount of torque on the mounting nut, when reinstalling the prop, critical? Is it okay to snug it down tight and installing the new cotter pin? I don't have a torque wrench and was wondering if it was okay to "wing it"!

Thank you for your time and knowledge!

Gene


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## dailysaw (Jan 22, 2008)

i love mine..i take mine to the shop that way the warranty is still good. it prob dont matter if you do it yourself as long as you use there parts and such .i have a 4 blade prop and can turn 6000 rpm if i trim her.


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## feelin' wright (Oct 7, 2007)

Far as optimum crusing spped I typically always run mine 7-800 off of redline. The only way to tell what is optimum cruise is to get a flow meter.


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## dailysaw (Jan 22, 2008)

you still have a lot of power left to find..simple prop should do the trick. go cruise rpm is 4500-5500 depending on rig hull etc


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## dailysaw (Jan 22, 2008)

btw move this to boating tips and tricks and you will get more feed back


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## Lucky Dawg (Oct 6, 2007)

You should be getting 5000 - 6000 rpms. I have run mine at full throttle for hours on end. Change your oil every 6 months and you should be good to go. As for the torque, you can wing it.


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## jawjacker JR (Feb 18, 2010)

Make sure you have ten micron water seperator filter installed. Also change the fuel filters yearly or atleast every hundred hours... The only weak part on that motor is the fuel system, and really its just the crappy fuel we are getting now. It doesnt hurt the motor to run it hard. I like to prop them out to run 6000 rpms..


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## Sequoiha (Sep 28, 2007)

Like said you are not turning enough Rpms. Give me a call and I will gladly answer any questions you may have


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## inshorecatch (Oct 1, 2007)

what year is your motor


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## WhackUmStackUm (Jan 31, 2010)

The primary powerband is 5000-6000 RPM. However, you will likely use more gas/hour then you do now. Sounds like you may need a prop with less pitch to get to the higher RPM.


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## 230 Cobia (Mar 25, 2008)

Sounds like you have too much pitch mine runs full out at 5800 rpm cruse at 3600 for best millage but I have much larger boat with twins If I were you I would Call Kenny per previous post


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## MyTimeToPlay! (Feb 11, 2011)

feelin' wright said:


> Far as optimum crusing spped I typically always run mine 7-800 off of redline. The only way to tell what is optimum cruise is to get a flow meter.


 Thank you for your reply! I have a digital RPM gage and wouldn't know where 7-800 off redline is. Is there a way to tell. I may be missing a bar "graph" telling me where I am as far lowest to highest RPMs.


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## MyTimeToPlay! (Feb 11, 2011)

230 Cobia said:


> Sounds like you have too much pitch mine runs full out at 5800 rpm cruse at 3600 for best millage but I have much larger boat with twins If I were you I would Call Kenny per previous post


I will and thank you very much for taking the time to post a reply!

Gene


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## MyTimeToPlay! (Feb 11, 2011)

dailysaw said:


> you still have a lot of power left to find..simple prop should do the trick. go cruise rpm is 4500-5500 depending on rig hull etc


 Okay I know the pitch effects rpms and thrust but if you have more rpms and less pitch how does speed come out in the end? What pitch will give me the most rpms and speed? Thank you for taking the time to educate me!

Gene


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## MyTimeToPlay! (Feb 11, 2011)

Lucky Dawg said:


> You should be getting 5000 - 6000 rpms. I have run mine at full throttle for hours on end. Change your oil every 6 months and you should be good to go. As for the torque, you can wing it.


 Thank you! Great knowing I won't blow it up running wide open.... I seem to raely run it wide open (probably no more than 5 minutes total in the 6 or so times I have had it in the water since I bought it) because I don't want to blow it up. Thanks a million!


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## MyTimeToPlay! (Feb 11, 2011)

jawjacker JR said:


> Make sure you have ten micron water seperator filter installed. Also change the fuel filters yearly or atleast every hundred hours... The only weak part on that motor is the fuel system, and really its just the crappy fuel we are getting now. It doesnt hurt the motor to run it hard. I like to prop them out to run 6000 rpms..


 It does have the ten micron filter. Do you know how often that should be changed? I have used nothing but ethanol free gas and always use Yamalube Ring Free Plus and Yamalube stabilizer though I guess since I use ethanol free gas I don't need to use the stabilizer but I guess it makes me feel like I'm taking good care of the motor.


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## MyTimeToPlay! (Feb 11, 2011)

dailysaw said:


> you still have a lot of power left to find..simple prop should do the trick. go cruise rpm is 4500-5500 depending on rig hull etc


What is "rig hull"? Its a Cape Horn Offshore Series if that tells you anything. Also, is that a "good" cruise speed or "go" as in getting there quick? Thank you!


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## MyTimeToPlay! (Feb 11, 2011)

Sequoiha said:


> Like said you are not turning enough Rpms. Give me a call and I will gladly answer any questions you may have


 Thank you Kenny! I'll get a small list(promise) of questions together and give you a call. What is a good time/day to call you! Thanks Kenny!

Gene


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## MyTimeToPlay! (Feb 11, 2011)

inshorecatch said:


> what year is your motor


 Its a 2003 with about 130 hours on it.


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## Sequoiha (Sep 28, 2007)

MyTimeToPlay! said:


> Thank you Kenny! I'll get a small list(promise) of questions together and give you a call. What is a good time/day to call you! Thanks Kenny!
> 
> Gene


 Hey Gene, any time is a good time to call, im there from 0630 till 1700


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