# How to balance my jon boat with an oversized motor



## fatherfire89 (Jan 21, 2011)

I have a Lowe 1448 jon boat and I'm going to be getting a 50 HP 2-stroke Yamaha which I already have a jet pump for. Hopefully I can get 30 to 35 HP at the nozzle. The boat is rated for a 25 HP motor so I am going to build up the transom and put a steering wheel somewhere. But I don't know where to put the steering wheel and "captains chair." I like option A but I'm afraid there will be too much weight in the back with the oversized motor, center console, and steering components. Option B is basically a dashboard the width of the boat with a steering wheel on the right hand side. The stars with the numbers next to them indicate where the first, second, and third persons could sit. Note: I can put the battery and 10 gallon gas tank wherever. Usually it is just me when I go out on the river. What do you think? Option A,B,C, or other? I currently have a 25 HP Evinrude tiller with a jet pump on the boat which works fine for one person. I am getting about 15 HP at the nozzle. Two people and it gets pretty bogged down. 

THANKS,
Mark


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## bassboy1 (Jan 21, 2011)

I somewhat favor option C. With the jet boat, I imagine you'll be running rocky rivers, in which case having the forward console will be a big advantage from a vision standpoint. Throw your batteries up underneath the console.


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## richg99 (Jan 21, 2011)

I don't know the answer...but...I did look up the weights of the various motors. It appears that the weight difference is around 50 lbs, depending on the exact model. The battery and the fuel tank should weigh in around those numbers. Moving them forward would do a lot to offset the weight difference. Rich 

p.s. Battery should be around 50 lbs and fuel weighs approximately 8 lbs. per gallon.

*********************from the 'net **************************************

The dry weight of a 50 hp Yamaha outboard of the 2 stroke variety is 158 - 187 lbs, depending on the particular model.
------------------------------------------------------------------------------------------------
From the Boston Whaler site ContinousWave...a GREAT source of information, incidentally.
*********************************************************
The following are typical OMC motors and weights found on classic Whalers. Weights taken from the 1992 Evinrude catalog.

2 cylinder, 521 cc platform, 20/25/30/35 HP
15 inch shaft, rope start -- 115 lbs
15 inch shaft, elec. start -- 118 lbs
20 inch shaft, rope start -- 117 lbs
20 inch shaft, elec. start -- 120 lbs


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## benjineer (Jan 21, 2011)

D. Put the console on top of the center bench and a seat behind it. Just looks like the right place. Batteries/tank might go in front of the middle bench in a bench extension. Extra people could sit on that or on rear bench. I have no experience with jets.


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## CarlF (Jan 21, 2011)

Dont want to rain on your parade, but this topic has come up on here and many other sites before.

Be careful: 
I don't know about where you live, but here in Alabama, I can tell you that if our Marine police or wardens see a 50hp motor on a 14' jonboat, you're gonna get stopped. And if you get stopped with an over-powered boat, you are going to get a ticket. And its about $250.00 total with court cost. 

If you have an accident, your insurance will most likely not cover you. 
Worse yet, someone is injured, you're gonna be held liable.

IMO, you need a bigger boat if you need that much HP.


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## slabdaddy (Jan 21, 2011)

I agree with Carl; a lot of 16' are only rated for a 40. Good Luck!


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## Outdoorsman (Jan 21, 2011)

I also totally agree with Carl... was just waiting before i posted basically the same....
Also a hefty fine in Wisconsin... Risking everything if anyone got hurt and you got sued with NO insurance (even if you had insurance it would not cover ANYTHING that would happen with an overpowered boat)... I know...one in a million chance...but if it was me I would not risk it...

Just my $0.02....

Outdoorsman


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## crazymanme2 (Jan 21, 2011)

I run a 40 hp on my 1240v.I had an safty inspection(passed) & since I have done modifications to my boat it is no longer a factory boat so you don't have to stick to the hp ratings on the boat. =D>


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## CarlF (Jan 21, 2011)

crazymanme2,

Who inspected it? USCG? 
I just dont see how that HP would come out OK on a 12' open boat using their formulas.


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## crazymanme2 (Jan 21, 2011)

Sheriff inspected it.Didn't say anything about formulas.Just said because of the mods that I did it wasn't a factory boat no more.He did tell me there is max speeds on most inland lakes & rivers.


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## MDFisherman57 (Jan 21, 2011)

I would think if you properly add foam by the section that it may help keep it from dipping back so much.


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## redbug (Jan 21, 2011)

I am another one that would take the chance and risk someones life by overpowering a boat.
foam would n't help it is only used to stop it from sinking.. but then again with an over powered boat that could happen easily


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## richg99 (Jan 21, 2011)

More than anyone would want to know about legality; ratings; horsepower and boat sizes.. regards, Rich

https://continuouswave.com/whaler/reference/ratedHP.html


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## reedjj (Jan 21, 2011)

I like the idea of mounting a center console on the center seat. Or removing the center seat all together. there are some really cool ways to cut it down so it still maintains structural integrity and still pretty much remove it.

I have looked at doing this same thing. I was either gonna get a 1448 or 1542. I ended up with the 1542 because of the price. It is also rated for 25hp. If you get a 25 merc 4 stroke it weighs close to 200lbs and only has about 18hp at the pump. Those older 40hp and 50hp 2 strokes are lighter than the new Merc 4 stroke. So you should be fine as far as weight goes on the transom. You lose so much hp with the jet as compared to the prop. If you get a 50hp motor and add a jet it will really only be about 30-35 at the jet, so it wont be too much. (or so the jet guys tell me). We all know they rate the boats low for safety.

I was looking at getting the Tohatsu md35 jet. It is a 50 hp motor with 35hp at the pump. and only weighs about 10lbs more than the merc 25. I just think the merc 25 is way too little hp for a boat that size 18hp at the jet c'mon. The Merc 40hp 4stroke jet is not even an option it weighs a ton. The hp gain is barely enough to make up for the extra weight. I would love to have the tohatsu!

As for the law??? That is something else. of course you can always paint the motor or get different stickers for it. A 90's 2 stroke 40hp or 50hp outboard is no bigger is size (visual recognition) than todays 4 stroke 25hp or 30hp motors. 

Disclaimer.... If you get caught its on you. I would do it go for it! Keep us posted


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## lckstckn2smknbrls (Jan 21, 2011)

Have you considered adding Pods to the transom?


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## Specknreds (Jan 21, 2011)

The way I solved my weight issue was to add floatation pods. I'm not sure how a jet would act with them.

https://www.tinboats.net/forum/viewtopic.php?f=3&t=10254&hilit=floatation+pods


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## reedjj (Jan 21, 2011)

I always thought they would act similar to a tunnell.


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## Lil' Blue Rude (Jan 21, 2011)

Few years back I looked at a guys boat, blazer sport 15' 48" with a 50 yamaha jet on it. It was tiller handle, had one pedistal seat in the back and another about a rib in front of that. It didn't have balance issues. You don't need to put all the weight to the front. Most guys aroung here have gas tanks batteries behind the bench in the back and they usaully have the seat on or right in front of the bench. Tilt and trim will help alot to balance the boat while driving it. If it was me I would mount your console right in front of the back bench. I wouldn't mount a seat for a passegner to ride on the deck, depending on where your located they can give you a ticket for it. It's fine while your fishing, They've started to give ticket in Missouri this year for it. Set it up to suite you o=and your need. Just my opinion :mrgreen:


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## crazymanme2 (Jan 21, 2011)

Pods would be like trim tabs on the back.


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## fatherfire89 (Jan 21, 2011)

Lots of good input here, Gentleman. Thanks for the weights of motors richg99. Sounds like I can balance the added motor weight in the back by putting the battery in the front. And compensate for the center console in front of the rear bench by moving the gas tank up front. Any ideas on how to run a fuel line from front to back while keeping it relatively protected/concealed? Maybe I'll add float pods on the back if it is needed.


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## fatherfire89 (Jan 21, 2011)

reedjj: does your 1542 have a keel directly in the center of the boat or are the keels spaced so you get a clean apron of water going to the jet foot? I have a keel right in the center so I think I lose a couple of horses there. Just something to keep in mind. But ya, I would definitely go for the 50/30 or 40/25. My Evinrude 25 with a pump just isn't quite enough for two people...it takes too long to get on plane and while it's trying I am running the risk of sucking up rocks or even hitting submerged boulders. Plus the top speed is about 20 with one person, 16 with two.


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## reedjj (Jan 21, 2011)

It has one right down the middle with the plug in it at the stern. I don't have a motor just yet. I kinda gave up on the jet being that everyone here in FL thinks I am nutz for wanting one. I have been looking for a nice prop short shaft. But if I find a jet at a good price Im gonna get it. I don't care what they say!

I don't know a lot about them other than I really wanna be able to run shallow, and I just think they're cool. 

If you are losing power because of lack of flow of water to the foot due to the keel (I think thats what your saying??) you could try to play with the height of the foot a few mm down or maybe adding a jack plate (if you don't already have one) That would not only give you the ability to adjust up or down but it would also move the foot to the rear a few inches, giving you just that little bit of opportunity for clean water to enter the foot.

Like I said, I am no expert, but just from observation, and a lot of time researching jets I know that getting a good positive flow to the foot is very important. Just like with regular water pump any air or cavitation is going to cause a loss of output or in our case thrust/hp/tourque. The same goes for air to a turbo. You want the cleanest smoothest flow to the intake. Thats why tunnell hulls are so effective with jets. The hull basically acts like a RamAir (or ram water)system for the foot/intake. I would think that adding floatation pods and moving the jet foot back and inch or 2 would have the same effect. Flow of water from under the hull would rise right into the foot between the pods as it travels rearward.


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## reedjj (Jan 21, 2011)

I don't think over powering by a few HP's with a jet is as dangerous with a jet as it is with a prop. With jets you don't get the instant hit you do with a prop. There is turbo lag, so the stress on the transom is less of an issue.

Of course jet ski's hit pretty hard when you nail them. Fender66 has a 225Jet and I bet it hits like a 69 chevelle!


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## fatherfire89 (Jan 25, 2011)

I have messed with raising and lowering the motor and as far as top speed with one person is concerned, it is set just right. Thats a good idea about trying to move the motor back some. One of those spray plates would be nice too. The the anti-cavitation fins would just get torn to shreds in a couple of minutes around here though.


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## lckstckn2smknbrls (Jan 25, 2011)

fatherfire89 said:


> Lots of good input here, Gentleman. Thanks for the weights of motors richg99. Sounds like I can balance the added motor weight in the back by putting the battery in the front. And compensate for the center console in front of the rear bench by moving the gas tank up front. Any ideas on how to run a fuel line from front to back while keeping it relatively protected/concealed? Maybe I'll add float pods on the back if it is needed.


I have my fuel tank mounted up front. I ran 3/8" automotive fuel line in the space behind the ribs along the splash rail.


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