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I'm running a 2015 60hp mercury 4 stroke EFI on a 16 ft Tracker weighing about 1300 lb.. I have operated it in Ark. at 900 ft. elevation, C.J. Strike, and recently at Strawberry. It seems to do better at the lower altitudes. With only 1 larger passenger at Strawberry I had difficulty getting on plane. It has a 12x22 prop.. Is there a simple way to get better performance at the higher altitudes? The boat was purchased at Fred's so I would think that it would be propped for our altitude.
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Good fishing to all. Hue
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It is without a doubt a prop issue, Strawberry(7,612') is over twice the elevation of CJ Strike(2,457'). It was likely propped for our elevation on the valley floor but Strawberry is still several thousand feet higher.
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My boat is a 20' in board out board. I use a 17 pitch 4 blade at Utah lake and yuba and a 15 pitch 4 blade at strawberry and Bear lake. It had a 19 pitch on it. It sucked I sold it.
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18.5 Lund 150 Merc 4 stroke- I run a 19 pitch at Powell, a 17 pitch at Utah Lake Flaming Gorge, a 15 Pitch at Strawberry. Will not get on plane with the 19 at the Berry the 15 works great. Amen to both of the above posts gear it down get a smaller pitch prop to run at that altitude.
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Yep, practice changing props, carry the prop wrench and block of wood to change the prop with. Always carry spare a thrust washer if your motor has them and a spare washer and nut.
I run a 21 on Powell and down low, a 19 at mid elevations like Willard and a 17 at the Berry.
As was said, gear down when you've climbed a hill and your prop is the final gear.
Ideally you want your motor to be able to just hit max RPM with the prop you have on for the place you are at.
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I've read some where that you lose 3% HP for every 1000 feet of elevation gain from sea level. Also you may need to adjust your fuel to air mixture, it is probably running rich at that altitude. Prop change is the easiest to do.
My 25 HP merc ran like crap for the first bit at strawberry then cleaned up and ran ok, I don't know if it has a self adjusting mixture or what the deal was. Then when I got back to Cache valley it ran poorly then cleaned up again.
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Thanks to all who replied. As I suspected, I need different props. Suggestions on who has the best deals?
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Good fishing to all. Hue
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Check with the local marine shops, like Marine Products, they will let you borrow a prop to test it out. Once you find the right prop then you can start looking at prices.It took me a long time to find the right prop for my setup so I understand the struggle. I'll shoot ya pm about a good place to look for props.
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A lot of good information given here. Some things to keep in mind.
1) Almost every boat dealer will sell you undersized motors for your boat. It is a matter of cost, we want to spend less and the motor is the greater part of the boat, so cut the motor and cut the cost. If asked if the motor is big enough, they will either skirt the issue or flat out misrepresent the fact.
Sure, at lower elevations, they will be adequate, but I always suggest, a lesson I learned the hard way, that you get the biggest motor a boat is rated for.
2) With that large motor you can go from Sea Level to Strawberry and be OK without a prop change, but it will ever rev at Sea Level and you need to cut your speed while cruising or it will dog a bit at elevation.
3) Modern motors, which you have, adjust the fuel mix with their own on board computers, just like our cars and trucks do. It is the loss of HP and RPMs, and props are the easiest/only way to deal with the RPMs.
I have a way for you to pick your prop. If you enter the correct details it will give you several options that have worked well every time for me. And, like the others, I always kept two props on board. If one got damaged I could always change and get back to the dock, even if it did dog out or over rev.
[url "https://www.mercurymarine.com/en/us/propellers/selector/#/step-one"]https://www.mercurymarine.com/en/us/propellers/selector/#/step-one[/url]
Just fill out the information requested and it will even predict your max speeds.
[fishin]
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I have taken the information you gave and made some best guesses to fill in the gaps and I come up with the following props:
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Black Max 3 blade prop 13.75x15
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SpitFire 4 blade prop 13.4 x 15
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SpitFire X7 4 blade 13.5 x 15
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Vengeance 3 blade 13.375 x 14
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Total assumed boat weight with People and gear is 1739 pounds
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RPMs 5750
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Max boat speeds of 29.66 MPH at 7600 feet elevation.
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You need a new prop, go to A Rock marine in SLC and talk with them. They will help get you the right one !!
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[font "Comic Sans MS"][#800000]Todays engines are pretty much controlled with an on-board computer that constantly monitors engine and atmospheric conditions and adjusts accordingly. My last boat had a 2005 Merc Optimax and it had that feature back then. The jetting on your motor shouldn't be an issue.[/#800000][/font]
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[font "Comic Sans MS"][#800000]Other than the fact that unless that motor is the max hp for your boat - and I don't think it is for a 16 Tracker - you are seriously underpowered for that boat. My 16ft Tracker was rated at 90hp Max back in 2005 and I was underpowered with the 75 Optimax. But it is now water over the damn and you will have to live with it for now. Your answer lies in what everybody has said so far - it's the pitch of the prop letting you down. As you go up in altitude, the pitch number on your prop needs to be smaller. Example: I use a 17P in the lakes close to the Front. When I go to either the Gorge or Strawberry, I switch to a 15P. My engine is a 2017 Merc 150 Four-stroke on a 20ft ThunderJet. My engine is designed to run at full throttle at an RPM range of 5,000 to 5,800 with a bang limit of 5,900. With the 17P at home I'm turning about 5,350 but only about 4,750 at Strawberry. The 15P prop at Strawberry puts me back up to about 5,200.[/#800000][/font]
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[font "Comic Sans MS"][#800000]So go back to Fred's (they are really great folks to deal with) and discuss your prop options. And by all means, check your RPMs locally to see if you are in the full throttle range here at home. My boat came with a 19P which only got me 4,800 at home (Willard being the closest water). The dealer swapped out the 19P for the 17P with no questions and I bought the 15P for a spare and for higher elevation fishing. Hope this helps.[/#800000][/font]
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Bob Hicks, from Utah
I'm 81 years young and going as hard as I can for as long as I can.
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Don't know a whole bunch about boat motors and altitude but the CJ strike comment really got me interested in from Idaho raised there CJ is my all time favorite spot to fish just and haven't been there in over a year how is it going up there? Sorry to be off topic but I just love that place like no other!
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Thanks again to all for your inputs. This forum has such great members that are willing so share knowledge. I will be sure to try some different pitch props.
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Good fishing to all. Hue
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Only been there twice, so no real comment on general fishing. Sturgeon fishing was good both trips.
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Good fishing to all. Hue
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I'm not really familiar with props, but my thoughts are that in the same water conditions, the prop shouldn't be affected by altitude.
Since you're running an EFI motor, there's not a ton you can do with it unless you had a way to remap the computer. Air is less dense at higher elevations and the computer should be able to compensate for it to some degree. The first thing you can try is to reset any learned trims by disconnecting the battery for a bit.
If your distributor or cam angle sensor has an adjustment, your biggest gains will be had by increasing the base ignition timing by 2-3 degrees. Do this with a timing light and be sure you know the procedure for setting base ignition timing for your specific application. There's usually something that needs to be either unplugged or grounded out to disable fluctuations in the timing map that are constantly being made by the ecu to adjust for load and whatnot. You'll also wanna set it back to more of a factory setting once you get back to a lower altitude, as it will be too aggressive and may exceed any safety margins built into the original timing map. Once you understand it, its a 5 minute procedure that I think is worth doing. Good luck.
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