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Replacement Prop Suggestions?
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| ToddSky |
Posted on 08/22/11 - 10:47 AM
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I have a 1986 Outrage 18' with a 2006 Mercury 4 stroke 115 hp EFI engine. I recently damaged the prop and want to replace it. The boat came with a spare prop (new in the box) but the one on the boat is aluminum and size 14x13p while the new spare in the box is size 13.25x17p. My question is why would they be different and which size is correct?
Thanks for any help!
Edited by ToddSky on 08/22/11 - 11:28 AM
1986 Outrage 18' |
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| Joe Kriz |
Posted on 08/22/11 - 10:57 AM
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What size is the damaged prop?
17 pitch sounds more like it...
Sell the new 13 pitch if not needed.
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| ToddSky |
Posted on 08/22/11 - 11:27 AM
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Joe, the one that was on the boat and is now damaged is 14x13p the spare is 13.25x17p. You think I should just get the hub kit for the 13.25x17p and use that?
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| Joe Kriz |
Posted on 08/22/11 - 1:24 PM
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13 pitch sounds awful small for a 115 hp motor.
What were your WOT RPM's with the 13 pitch you had on there?
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| Tom W Clark |
Posted on 08/22/11 - 2:08 PM
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17" is way too much pitch. Whether you need a 13" or a 15" pitch prop (or something close to it) depends on whether your Mercury 115 four stroke has the 2.07:1 gear ratio or the 2.33:1 gear ratio. 1986 was around the time they changed it.
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| ToddSky |
Posted on 08/22/11 - 7:29 PM
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Joe, the RPM was around 6000 (I think) and cruised nicely when throddled back to 5000 RPM at on plain.
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| ToddSky |
Posted on 08/22/11 - 7:36 PM
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Tom W Clark wrote:
17" is way too much pitch. Whether you need a 13" or a 15" pitch prop (or something close to it) depends on whether your Mercury 115 four stroke has the 2.07:1 gear ratio or the 2.33:1 gear ratio. 1986 was around the time they changed it.
Tom, the engine is a 2006 Mercury EFI 4 stroke 115 hp, I have no idea what the gear ratio is or how that changes the prop I need. The one I have ready to install now is 13.25x17p. Is this the wrong prop to replace my 14x13p prop??? Should I just order the same one that was damaged?? This is very confusing and Mercury seems to rate a variety of different size props for this engine. I'm trying to push a 1986 Outrage 18' with a 2006 Mercury 115 hp 4 stroke. Thanks for any thoughts.
1986 Outrage 18' |
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| ToddSky |
Posted on 08/22/11 - 7:51 PM
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I went on QuickSilver Propeller web site and it seems that they are recommending 13" x19" for my boat. If I knew the specs for the 1986 Whaler Outrage 18 I might be able to get a better answer but I don't know the weight fully loaded and some other questions so I just got the reccomendation from the length of 18 feet at this site.
http://www.qsprops.com/prop-selector/...tor/#step5
NOW I have a totally new set of numbers to ponder!
Edited by Tom W Clark on 08/23/11 - 8:24 AM
1986 Outrage 18' |
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| Tom W Clark |
Posted on 08/23/11 - 8:15 AM
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The one I have ready to install now is 13.25x17p. Is this the wrong prop to replace my 14x13p prop?
Yes, as I already explained.
Should I just order the same one that was damaged?
No, not necessarly. You should only replace it if you know it was the perfect propeller. There are lots of propellers out there and the frequency of boaters needing propeller advice and replacement propellers is an indication that many, many of them are not propped correctly.
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| Tom W Clark |
Posted on 08/23/11 - 8:22 AM
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The gear ratio of your motor is listed on the Specifications page of your Owner's Manual and sometimes Mercury outboards have the gear set identified on the gearcase itself with a decal.
At any rate, I am reasonably certain your 2006 motor uses the 2.07:1 gear ratio. Answer a few questions and we will see what propeller recommendations we can come up with. The Quicksilver prop calculator is obviously doing a lousy job of recommending a prop.
How fast does your boat go at WOT?
What is the engine speed at WOT?
Where on the transon is the motor mounted? What set of bolt holes is being used now?
Do you have any unusually heavy accessories onboard your boat?
Where and how do you use your boat? What is a typical load for you?
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| Fishmore |
Posted on 08/23/11 - 8:29 AM
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I just worked with my friend to prop his Outrage 18 1984 model with a 2006 115HP Mercury 4-stroke Saltwater edition motor.
This motor has a 2.07 gear ratio. The aluminum 13.25 x 17 Black Max prop performed well producing 40-41 mph average at WOT. That is what he is running now.
A 13.25 x 19 Stiletto stainless steel prop was too much for the engine and top speed was around 35-37 mph as we took too long to get on plane and performance was sluggish.
We have ordered and are awaiting delivery on a Stiletto 13.25 x 15 pitch stainless steel prop.
Before we settle on a prop we will probably also test a 13.25 x 17 Stiletto prop unless the 13.25 x 15 ends up getting the motor to 5750 - 6000 rpm at WOT.
(I do not want to confuse this post with his tachometer readings because his tach is not working correctly but, the tach works good enough to see how the change in pitch affected the RPMs. I hope to have the tach fixed before the next round of testing.)
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| Tom W Clark |
Posted on 08/23/11 - 9:50 AM
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If the 13-1/4" x 17" BlackMax is hitting 40-41 MPH at WOT the engine speed can only be about 5200-5600 RPM.
That is WAY too low for a motor with a recommended WOT range of 5800-6400 RPM.
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| ToddSky |
Posted on 08/23/11 - 9:25 PM
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Tom thanks for all your info I was hoping someone would just tell me what to buy. lol I don't know my boats top speed at WOT because I don't have a speedometer on the boat. I noticed that changing from Fish and SKi to Off Shore Fishing on the Quick Silver Prop calculator, gave me the 13.25x17p propeller that I have now. Otherwise it keeps recommending the Black Max aluminum 13x19p. The gear ratio is 2.07:1 the motor is mounted on in the middle of the transom with four bolts through the transom. The average load seems to be about 700 lbs. I plan to use it for fishing and pulling the kids on a tube. both in salt and fresh water. With the broken prop 14x13p I would run at 6000 RPM with the WOT but throttled back to run at 5000 RPM because I thought it was bad to "red line" the engine. This is my first boat so excuse my ignorance, I've already drove over a stone wall submerged in the middle of a lake!!
Edited by ToddSky on 08/23/11 - 9:33 PM
1986 Outrage 18' |
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| ToddSky |
Posted on 08/23/11 - 9:30 PM
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Fishmore wrote:
I just worked with my friend to prop his Outrage 18 1984 model with a 2006 115HP Mercury 4-stroke Saltwater edition motor.
This motor has a 2.07 gear ratio. The aluminum 13.25 x 17 Black Max prop performed well producing 40-41 mph average at WOT. That is what he is running now.
A 13.25 x 19 Stiletto stainless steel prop was too much for the engine and top speed was around 35-37 mph as we took too long to get on plane and performance was sluggish.
We have ordered and are awaiting delivery on a Stiletto 13.25 x 15 pitch stainless steel prop.
Before we settle on a prop we will probably also test a 13.25 x 17 Stiletto prop unless the 13.25 x 15 ends up getting the motor to 5750 - 6000 rpm at WOT.
(I do not want to confuse this post with his tachometer readings because his tach is not working correctly but, the tach works good enough to see how the change in pitch affected the RPMs. I hope to have the tach fixed before the next round of testing.)
Thanks for the information that 13.25x17p Black Max is what I have now to use. I have not tried it ,the Quick Silver web site keeps pushing the Black Max aluminum 3 blade 13x19p for my boat by weight and by length.
Edited by ToddSky on 08/23/11 - 9:31 PM
1986 Outrage 18' |
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| Fishmore |
Posted on 08/23/11 - 9:42 PM
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Tom, my understanding is that the service manual calls for WOT at 5000 - 6000 RPM at WOT. I double checked a few other sources to confirm. One source said max prop HP/RPM was 115.3/5500. So 5600 should be a good rpm for this engine according to that information. When my friend gets back from vacation I will check his service manual again to be sure.
Toddsky, try the 17 pitch prop and let us know what RPM you get at WOT. If you have a portable GPS (Garmin Nuvi or the like) it will display your speed over ground if you take it on the boat with you. When installing the new prop don't forget to grease the prop shaft with a waterproof marine grease and tighten the prop nut to around 55-60 foot lbs of torque.
Edited by Fishmore on 08/23/11 - 9:50 PM |
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| Tom W Clark |
Posted on 08/24/11 - 6:21 AM
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If the Mercury 115 is a L4NA (and in 2006 I believe it was), then the recommended WOT range is 5800-6400 RPM and only getting to 5600 RPM at WOT is most certainly bad.
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| Fishmore |
Posted on 08/24/11 - 8:48 AM
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Todd, it might be wise to check the motor to see if it is a L4NA or not. My friends motor is not an L4NA and it was manufactured in the same year as yours but, you never know as stranger things have been true.
If your motor is an L4NA it might explain the 13 pitch prop you had on it before as that motor had a higher RPM at suggested WOT then it's predecessor of the same HP.
Tom, I thought the L4NA was manufactured in 2007? I believe it supported the Smartcraft gauges where as it's predecessor did not. I also believe that the cowling on the L4NA was rounded where as the older model was more rectangular.
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| ToddSky |
Posted on 08/24/11 - 6:26 PM
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Ok gentlemen here is the data I found the engine (I don't have the owner's manual) so here goes...Mercury 115hp manufactured in Jun2006 1732cc, Idle speed in gear 700, Max RPM 6400, weight 410 lbs, 115XL4S, Model #115F23HD.
I don't see anything that says L4NA. My cowling is rounded at the top.
As for the sea test on my 13.25x17p prop it will have to wait we have a hurricane coming and work is getting in the way too. But I will let you know the speed at WOT and RPM because I do have a GPS. Thanks Again!!
1986 Outrage 18' |
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| Fishmore |
Posted on 08/24/11 - 10:15 PM
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Todd - Looks like Tom was right and you have the higher RPM motor. As Tom suggested don't bother with the 17 pitch prop it will not work well.
Armed with that information I would sell the 13.25x17 prop. Or you can see if you can trade it for a 14x13 Black Max like the one you damaged. If you can not get a trade then see if you can borrow a Black Max 14x13 pitch prop. Then run some WOT tests and post the RPM/MPH results for suggestions on a better prop.
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| Tom W Clark |
Posted on 08/25/11 - 9:36 AM
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With a L4NA Mercury 115 on an Outrage 18 with the 2.07:1 gear ratio, you are going to need a 15" pitch prop, so, no, the 14" x 13" is definitely not a good choice for a replacement propeller.
I also cannot recommend the aluminum BlackMax propellers. If you want a Mercury brand prop, use the 13-1/4" x 15" Vengeance stainless steel propeller.
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