# which motor should I get?



## cusnooking (Jan 17, 2007)

yobata said:


> I picked up a "homemade" skiff and am trying to figure out which motor to mount on it (there is no capacity/ max hp plate on it) - would a 20hp 4s tohatsu short shaft (w/ power tilt and elec. start it weights in at 136lbs) be okay for this? I have thought about getting a used 2 stroke 25hp because they are relatively light, but I decided to buy new for peace of mind.
> 
> The length is 14' and the beam is right at 5' (it is a wide boat), the transom is very solid. (I will be removing that metal jack plate that is on in this photo).
> 
> Does anyone know how i can determine max hp rating on this boat? Is there a formula for doing this?


I run a 20 horse tohatsu 4stroke on my same type boat runs good reliable it gets 25 miles an hour with just me


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## Vertigo (Jun 3, 2012)

Speaking from experience with many boats of that size and construction, anything between 15 to 25 hp would probably work. You'd get about 23 mph WOT with a 15 and you might nudge 30 with a 25. The 15 would probably be the best tradeoff between weight, economy and performance. If you're on a budget, the decision should probably depend on which motor you find that turns out to be the best deal.


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## yobata (Jul 14, 2015)

Thanks for the replies! I'm not going to need to run very far, I'm on the space coast and just need to be able to quickly cross the Indian/banana rivers if a storm comes.


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## Capt Dan Medina (Apr 28, 2008)

That 20 should do you plenty fine, and the power tilt and trim and electric start will be options your happy you have down the road. Just work on getting the fuel tank and battery forward for good weight distribution. 

I will say the get up and go from the 2 stroke Yamaha is killer, but given the choice between the two, you really can't go wrong.

Good luck and tight lines!


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## CurtisWright (May 9, 2012)

The coast guard has a publication for calculating maximum horsepower for a homemade skiff. Just Google it. 

But yea, I'd say get a 20 4 stroke


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## yobata (Jul 14, 2015)

Thanks Capt Dan and Curtis. I am having a hard time tracking down a permanent plastic gas tank that is smaller than 12 gallons. I am looking for something in the 5-8 gall range. I can only find aluminum tanks that small. Does anyone have any leads? I am trying to keep it as light as possible, and more than 8 gallons is really overkill for that efficient motor. Should I just get the aluminum tank? Do metal tanks needs to be "grounded" somehow??


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## LWalker (Aug 20, 2013)

Moeller FT0704 7 GALLON 12.00"L x 12.00"W x 12.00" H

But I think I would just go with a portable tank to save weight, cost and time.


Coast Guard 183.53
http://www.gpo.gov/fdsys/pkg/CFR-2001-title33-vol2/pdf/CFR-2001-title33-vol2-sec183-53.pdf

If it has a 20" transom and you are using remote steering, then it appears that it would be a 50 hp max.

If less than a 20" transom and/or you are using a tiller, then it would be 31hp.

Please double check my math.
*
*


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## bobber (Sep 29, 2015)

Your hull appears to be a Johnsen Starfisher or a clone of it - same size as yours - it was rated at 25hp.
http://www.fiberglassics.com/wiki/images/f/f8/Johnsenbxx002.jpg
http://www.fiberglassics.com/library/File:Johnsenbxx001.jpg

Current 25hp + 4S engine will be too much weight on that hull so the 20 Tohatsu/Nissan/Merc or Suzuki are your best options if you want new. All of these engines come with a 3gallon tank, given their fuel efficiency (10 mpg) you'd have a hard time emptying that.

I'm running a 20 Tohatsu on my Johnsen 15', best I can get is 24mph with just me aboard.


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## yobata (Jul 14, 2015)

Thanks lwalk! I want to mount a permanent just to not have to take the tank out every time to refuel.


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## CurtisWright (May 9, 2012)

My vote is twin 3 gallon portable tanks. They are light weight (~20lbs full) and easy. You can take one on short trips and you have the ability to stash 3 for a longer trip.

The best benefit is you can seal them tight and store them in the shed or garage to help keep condensation to a minimum.


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## yobata (Jul 14, 2015)

After trying to figure out what all is involved with setting up a permanent tank, I think the portables might be my answer. I knew I'd have to get a fill, vent and send line hookup, but I was completely baffled by the 'return' fitting... So now I'm going with the simple portable with the vent in cap system... No fuss, no muss. The 4 stroke 20hp tohatsu will run all day on 3 gallons anyway


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