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pbear

What motor to put on my Lund.

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pbear

I have an older 14 foot lund that I have put a floor in. It says that the boat is rated for a 25 hp motor. Has anyone put a larger motor on their boat then what it was rated for? I'm trying to get the best of both worlds, a boat That is decent for fishing but also big enough to pull my kids behind in a tube or on waterskis. Both kids are quite light. My 20 hp Yamaha outboard does not fit the bill. Let me know what you think

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AB

Move up to a 25hp if that is what the transom is rated for.



You could go higher, but you place yourself "at peril" if anything goes wrong and the authorities start going over your rig with a fine tooth comb. for example looking to dodge an insurance claim or find you responsible for something that happens on or off the water where the boat is involved.



If you find you need more power, realistically, your looking for more boat too..



iceman


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pbear

Does 5 hp make that big of a difference? Moving from 9.9 to 15 is a huge difference. Wondering if the difference in horsepower from 20-25 means a big difference off the start and also top end. I might be looking for a 25 if anyone has one for sale.

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AB

Does 5 hp make that big of a difference? Moving from 9.9 to 15 is a huge difference. Wondering if the difference in horsepower from 20-25 means a big difference off the start and also top end. I might be looking for a 25 if anyone has one for sale.

What you might find is that moving from a 20hp to a 25hp engine can open up the range of props available to you. Changing prop pitch can dramatically effect the performance of the boat.

For pulling power, a lower pitch prop can improve the hole shot, but you will sacrifice a top end speed. If the pitch is to high, it will take a longer time to get up on plane, but once you are there.....

I doubt the difference in top end speed is going to be a heartbreaker on something in the 20hp to 25hp range. But having fun with the kids is priceless. See if you can get a different pitched prop for your 20hp and save some cash for gas if it works!

have fun on the water!

iceman

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naden

The noticeable difference will also depend on the motors. A friend of mine had a '79 evinrude 25 hp 2 stroke on a 14 foot lund, last summer purchased a brand new yamaha 20 hp 4 stroke. With two people in the boat he only lost a few km an hour on the gps on plane and the boat seems to accelerate fairly fast with the 20. This was before the new engine was properly broken in.



With the two of us in the boat (about 400 lbs) which is a 14 deep and wide lund with fishing gear and anchor it would do about 39 k/hr with the yamaha.



Keep in mind that if you have an older motor (roughly early 80s or earlier, I cant remember exactly) the hp ratings of some manufacturers will be calculated at the crank and not the prop. Any motors newer than that will be rated at the prop shaft. In my friends case his old evinrude was probably only in reality a 22 hp engine. Also consider that it was an old tired engine with possibly some wear on the prop and you can see why the difference was negligible.



Also keep in mind that if considering a newer 25 hp 4 stroke the engines are way heavier than a 2 stroke 25 hp or a 20 hp 4 stroke. Older boats will have a tough time supporting the weight of a newer 25 4 stroke on the transom. This is why my friend opted for the 20 hp 4 stroke over a new 25 hp 4 stroke.



Personally, if the transom is in good shape and I could find a 30 hp 2 stroke that did not weigh more than the 25 hp motors manufactured in the same era as your boat, I wouldnt worry too much about being 5 hp over the hp limit. I would keep an eye on the transom though and ensure that the added power is not beating it up too bad.



Another friend of mine had a 14 ft lund deep and wide with an 80s 30 hp johnson, the only problem he had was that the boat would not troll slow enough with only a few people in the boat. His boat did not have floors though so in your boat that might not be a problem.


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naden

Im not that familiar with 20 hp yamahas but another option that might be worth exploring is converting your 20 to a 25 if the powerheads are the same for that year and model of engine. It is common for outboard manufacturers to save on manufacturing costs and "detune" their engines to create motors with lesser hp. Common ways that different manufacturers accomplish this include different size carbs, blanked off or restricted reed valves, and different exhaust tubes. There is a a TON of misinformation on the web about doing this and many people do not fully understand how to do it properly. The only way to know for sure is to get your hands on a parts schematic for both the 20 and 25 hp of the same year and comepare the p/ns for the engine and also the prop. Then either order the parts required or look for used parts on ebay or possibly a parts donor engine.



Many people think that this can be done by changing the jets, which is not true. Changing jets will only change the mixture of fuel to air and will make the motor run like crap.



Crooksyredboat, if your looking for a 15 hp yamaha there is a 9.9 on kijiji right now, these motors are easy to upgrade to a 15 hp. I looked into doing this myself last spring but ended up finding a 15 hp that I purchased, great motor.


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Pro fisherman-Stud Muffin

ya dont go over! but max =hp is pretty much what you need on most boats, better fuel econ, better performance.

in the 90s and up i think most manufacturers 20hp had 2 holes & 25 hp got you an extrax cylinder , merc and johnson had 3 cylinder 25hp. while yammy was 2 cyl till 30-40 hp? i think??? i could be wrong

the 3 cyl will have more displacement, better top end and run smoother. getting a few extra cubic inches helps but and extra cylinder will wake it up.

if the upgrade doesnt get you more cc's or cylinders the gains wont be as noticeable. IMHO.


><^> ........ <^><

 

2016 Dog Lake Open Champion.

Thunder Bay BASSmasters Vice-President 

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levi64

I wouldn't go above what the boat is rated for and if your pulling any weight behind its, going to put extra stain on the transom. You're gonna need a bigger boat.


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Adrian

I have an older Lund S14 (1977) with a 15 inch transom. I had a 1981 Johnson 25 hp on it for years, and it performed quite well. In 2004 I removed the center seat (leaving the bottom part of the seat support) and put in a flat floor from the rear seat to the front seat. I braced the sides where the center seat was. This added about 75 lbs to the boat. This made the boat a much more friendly fishing boat. Top speed with my wife and I was about 24 mph on the gps. In 2006 I bought a new 25 Merc 2 stroke with electric start. I use a small lawn tractor battery. This motor performed much better than the Johnson. It idled better, burned a little less fuel, and now the top speed is about 27 mph. The thing about the Lund boats of this era is that their transoms are weak. Mine started to bend just from engine thrust. When you crank on the power, you can see the engine sit back and see the transom start to bend. Since bracing it, this does not happen any more. I am very happy with the 25 Merc. I knee-board behind it all the time (and I am not a lightweight at 200 lbs), and have pulled the kids on skis and knee-boards for years. The Johnson did a little better job of it, as it has a little more torque at the bottom end, but the Merc is faster (the Johnson is 512 cc and the Merc is 400 cc). I would not go to a 30 on these boats, nor would I go with a 4 stroke, just because the transoms are a problem, and the extra weight. I used to run a transom mounted electric trolling motor and had a group 24 battery at the back. This made for long slow climbs to get onto step, and as soon as you slowed down a little to navigate a river for instance, the boat would fall off step too soon. I no longer use the trolling motor as the Merc does that well.



Just my 2 cents worth


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pbear

Found a 25!! Now we just need this snow to melt. Shooting for June 15th!

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Adrian

If you are going to wait till the ice goes out, the motor will be a year older.....


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pbear

I have an older Lund S14 (1977) with a 15 inch transom. I had a 1981 Johnson 25 hp on it for years, and it performed quite well. In 2004 I removed the center seat (leaving the bottom part of the seat support) and put in a flat floor from the rear seat to the front seat. I braced the sides where the center seat was. This added about 75 lbs to the boat. This made the boat a much more friendly fishing boat. Top speed with my wife and I was about 24 mph on the gps. In 2006 I bought a new 25 Merc 2 stroke with electric start. I use a small lawn tractor battery. This motor performed much better than the Johnson. It idled better, burned a little less fuel, and now the top speed is about 27 mph. The thing about the Lund boats of this era is that their transoms are weak. Mine started to bend just from engine thrust. When you crank on the power, you can see the engine sit back and see the transom start to bend. Since bracing it, this does not happen any more. I am very happy with the 25 Merc. I knee-board behind it all the time (and I am not a lightweight at 200 lbs), and have pulled the kids on skis and knee-boards for years. The Johnson did a little better job of it, as it has a little more torque at the bottom end, but the Merc is faster (the Johnson is 512 cc and the Merc is 400 cc). I would not go to a 30 on these boats, nor would I go with a 4 stroke, just because the transoms are a problem, and the extra weight. I used to run a transom mounted electric trolling motor and had a group 24 battery at the back. This made for long slow climbs to get onto step, and as soon as you slowed down a little to navigate a river for instance, the boat would fall off step too soon. I no longer use the trolling motor as the Merc does that well.

Just my 2 cents worth

Adrian, what did you do to brace the boat transom? The Lund I have is slightly newer bit I removed the rod holder and live well from the venter section of the boat. Pedestal mounts were added to the floor when I replaced and put vinyl on the plywood floor. I've never noticed any issues with bending or flexing (so far). Hopefully the bigger motor does not create an issue.

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pbear

I used the gps on the boat this weekend. With my son, my dog and myself loaded for fishing, we managed 35 km per hour with the 20 horse yamaha. With the 25 horse johnson we topped out at 41 km per hour. I decided to sell the yamaha an keep the johnson. With nearly 500 pounds of anglers, we still managed 36 km let hour. Plenty of power to pull the kids around (hopefully)

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