# Raft Motor...What's the best?



## calendar16

glad you asked...

cause I have been doing a bunch of research lately so figured I would chime in what I have learned...I don't consider myself an expert by any means or through experience cause I have minimal but I have read a lot in the past couple months cause we are renting one for our upcoming Cat trip. The rental was a last minute discovery so I was fully preparing myself to purchase thus all the reading...

BEST?

Mercury, Suzuki, Honda, Yamaha, etc. Supposedly the Suzuki outboard has the most output of similar sized engines.

HP? 

I would pay close attention to weight cause there is a huge jump from say a 6hp motor to a 9.9+. You can get good 4 stroke 6hp for less than 60# going up to a motor larger than 6hp you gain another 20# at the minimum. Less is more when it comes to weight for a motor in my opinion especially since you will have to stow it for rapids, etc.

LONG VS. SHORT?

This will all depend on how high your transom is from the water line. If you have a lot of stern rise on your raft i.e. more than 17inches from the top of the transom to the water line you would need to get a long shaft so that the propeller gets enough of a bite on the water.

AIR COOLED VS. WATER COOLED?

Water cooled is going to run a lot quieter but could also mean you have more maintenance especially on really silty water. Most engines are water cooled with the exception of the Briggs & Stratton motors. I would go with water cooled over air in my opinion.

2-STROKE VS. 4-STROKE?

Go with a 4-stroke. The EPA is really pushing to prohibit 2-strokes on more and more riverways to reduce the pollution in the water. If you are going to invest in a motor might as well adapt to future regulations and just get a 4-stroke.

groovy!

-Cal


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## brandob9

Has anyone had trouble with the 4-strokes lying on their side for extended periods of time?


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## oarboatman

Do Not ever start a 4stroke motor that has been any which way other than up with out pulling plugs or you can bend the crankshaft when the oil leaks into the combustion chamber and the piston is at the top of its stroke. Or, give it a go and you'll have a great anchor...


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## Dave Frank

I have the B&S 5hp, I believe. It is loud. I feel like I am mowing the lawn. I was not aware of the on its side concern, but it makes sense. It must be OK to keep the back end as the top end for storage, because it can tilt to that location on its own mount.

I broke the main piece of hardware that the thing steers and raises from, but that probably would have happened to any motor that takes a good hit while running backwards with the current and a heavy load.

Look closely at the weight. Most brands carve 2-3 sizes of motors out of the same head. Look to get the biggest one out of the smallest head to save weight. More power will not make a self bailer go any faster, but it will provide better maneuverability, especially with bigger pods of boats. With cats the more you get the faster you go. I saw a medium sized cat with a 25 once. He said it could plane out.


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## desertrat

oarboatman said:


> Do Not ever start a 4stroke motor that has been any which way other than up with out pulling plugs or you can bend the crankshaft when the oil leaks into the combustion chamber and the piston is at the top of its stroke. Or, give it a go and you'll have a great anchor...


Many designs allow you to lay at least the larger 4strokes down provided its on a flat surface and the bottom of the motor is not elevated. If you store it wrong you are looking at major engine damage like oarboatman says.


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## yarmonymatoid

I saw a guy with one of these pushing a cat and two rafts down Ruby Horsethief into a decent wind. He was totally stoked about it. He said he's had 5 boats including his pushing across Powell. Not overly noisy either. I'm considering ordering one for next season.

2.5HP Outboard Motor - 2 Stroke


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## brandob9

Weed whacker with a prop. This could be interesting. I'd love to see it in action.


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## Dave Frank

brandob9 said:


> Weed whacker with a prop. This could be interesting. I'd love to see it in action.


Awesome! you could bring the other attachments to mow all that obnoxious vegetation around camp too! (JK) of course.

I wonder about some of those long shaft things you see in Asia. If the prop didn't turn 90 degrees, it wouldn't steer as well, but I bet a lot of power is lost to the gear turn, that isn't entirely necessary.


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## kazak4x4

Sorry to dig up this thread, but how does the weed whacker doing now? Has anyone bought it? Like it?

Thanks,
Alex


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## Moon

Does anyone know how to convert the thrust measurment of an electric trolling motor into the horsepower measurement of a gas engine? I was looking at a used trolling motor with 55 lbs of thrust but don't know how many hp that equals. The salesmen at cabelas were no help.


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## Avatard

Moon said:


> Does anyone know how to convert the thrust measurment of an electric trolling motor into the horsepower measurement of a gas engine? I was looking at a used trolling motor with 55 lbs of thrust but don't know how many hp that equals. The salesmen at cabelas were no help.


Very low. A large industrial motor pulls 20A at 120v to do close to 2hp so a 12v motor that is 2hp would probably be close to 200A? I think ideal is close to 750w = 1hp. Not accounting for losses. 

Plus there is battery weight. Hard to beat a gasoline engine for power density


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## chateaunoname

*4-stroke*

I bought a 5 hp Mercury, long shaft 3 years ago. I have pushed 3-16' cats against the wind 4-5 mph. Water cooled and quiet. The Mercury motor can rest on one side safely, which is great for trips like Deso where you don't need it after the first day. I did screw up and put the motor end down and had to have the plug pulled and the cylinder flushed out once. Lesson learned. You can set the speed and tighten the tiller so it is very easy to use. I bought an extended tiller from Cabela's and that lets you sit away from the motor some. They are expensive, but for the first part of Deso, Cataract and the end of Westwater well worth it.


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## kennyv

I just bought a Tohatsu 4-stroke, 6hp, long shaft, water-cooled. It weights 60 lbs. and is about the same weight as the 4 or 5 hp. It's a bomber engine. Apparently Tohatsu makes all Nissan outboards and all Mercury outboards up to around 40 hp. The owner's manual states specifically which way to store it when on it's side and it has an integrated gas tank as well as the option for a separate tank. Basically, a 1-day westwater would be fine for the 1/3 gal. integrated tank, and a Cataract would do well with a separate tank. My buddy Mike at Eddyline Welding made an aluminum transom here in Moab. The whole setup is pretty solid. I'd recommend it to anyone.


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## SummitSurfer

@Kennyv.....got pictures? Thanks


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## salmonjammer

*7.5 Honda*

I have used my Dad's 7.5 HP Honda for years. Barrow it off of his fishing boat. I like that it is quiet. Wish it was a long shank. I would advise a long shank. It is easier to lift the motor mount up than it is to lower it. The short shank seems to cavitate easily. We have used it probably 6 times on the salmon-snake. It is a life saver when the up stream wind starts up. pushes 4-5 boats without too much trouble. The 4 stroke doesn't stink as bad as a two stroke!


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## kennyv

Summitsurfer:

I don't have any pics yet. The transom is getting a little upgrade soon. Basically it's a 'ladder' type transom. Two bars connected to my frame that run straight back over the stern of the boat. The transom itself is two pieces of 1" x 6" Trexx bolted to an aluminum plate. The upgrade is a small piece of diamond plate that will hold the power head of the motor when I'm rowing rapids. The prop will go in a bucket, strapped down to the back part of the transom. To keep the power head above the prop (owner's manual storage specs.) I will rig the spare parts ammo can underneath the power head. I'll post pics once it's all finished. The model I purchased was the MFS6CDL. 

Here's a link to the Tohatsu page: Tohatsu Outboards: Authorized North American Distributor for Tohatsu Outboards, Parts, & Accessories.

I hope this helps.
http://www.tohatsu.com/outboards/6_4st.html


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## mraible

*Honda BF5 5HP 4 stroke*

Hey all,

I'm getting a motor + motor mount for a trip down Desolation Canyon in a couple weeks. The guys at Down River said they had a customer who got a Honda BF5 5HP 4 stroke and seemed to recommend it.

I found a place I can pick one up in DTC. 

Honda Marine 2014 BF5AK3SA

Does anyone have experience with this motor? We have a 14' Down River Pro 140, and expect to have a push a couple other boats of similar size.

Thanks,

Matt


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## synergyboater

I ran a lot of grand trips with 30 hp hondas, great motors but had carburetor issues. We have had really good luck with tohatsus. My personal motor is a 6hp 4 stroke tohatsu, awesome for deso, cat, & WW type trips. Also, several brands smaller motors are actually made by tohatsu.


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## B4otter

My 1999 Honda BF5A (5 HP 4 stroke) pushed 7 rafts from Separation to Pierce Ferry at around 6 mph last Saturday (August 16). Ran like a top and always has, good low end torque and cruises at just over idle, maybe 1200 rpm. We used just over 2 gallons of gas pushing those 40 miles... 
Long shaft is best for any motor to be used on a raft, and 4 strokes now mandated on many rivers - but you can get great deals on old(er) 2 strokes, and if the river you're going to use it on doesn't ban them there's no real reason to go for a four stroke (which do tend to be slightly heavier). For storage, even if you put power head down all you need to do is stand upright for an hour or two, pull the spark plug (s) and yank on the starter cord until all that comes out is air. 
Outfitters now running Hondas in GC (Hatch and others) say no more carb issues... Any small outboard, 2 or 4 stroke, neeeds TLC. Change the gear oil often (every other Cat trip for mine, or 100 miles), keep the engine oil full, and set the valves once in awhile. I carry a spare spark plug, prop, and small tool kit but have seldom had to use it. Fresh gas also helps - I put the old in my vehicle and buy fresh every time I'm on my way somewhere with the motor. 
The "black oar" (comes from the days when all we had were Mercs, because they didn't drown) sure beats rowing miles of flat water into the wind...


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## chateaunoname

I purchased a 5hp Mercury 4 stroke five years ago. It will push 4 boats counting my 16' cat. Long shaft and a tiller extension. Very quiet. When I bought for the first part of a Deso trip, I could have bought a Honda, but it was $250.00 more. I am sure it would be good as well. You can lay it on one side as long as the motor is higher then the prop. Have it winterized every year.


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## Osseous

5hp is fine for a 14' boat- but you're putting a lot of load on that little block with a multi-raft rig. Not saying you can't do it- obviously the poster above has had good success. I'd want more torque in that situation so you can move AND steer.

Tohatsu makes really good small outboards- hard to fathom if you're not into outboards, but in that community they have a great reputation. Keep an eye on weight- some of these are VERY heavy for their displacement. Hard to get a dud anymore among the big names......just add Tohatsu to the list. 

Sent from my SM-N900V using Mountain Buzz mobile app


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## asleep.at.the.oars

when I bought my 6hp Tohatsu, they made a point of selling me the shallower pitch prop since the forward speed would be slower compared to rpm's pushing multiple boats. New this year, but it's run well so far. I pushed a total of 4 boats easily.


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## caverdan

mraible said:


> Hey all,
> 
> I'm getting a motor + motor mount for a trip down Desolation Canyon in a couple weeks. The guys at Down River said they had a customer who got a Honda BF5 5HP 4 stroke and seemed to recommend it.
> 
> I found a place I can pick one up in DTC.
> 
> Honda Marine 2014 BF5AK3SA
> 
> Does anyone have experience with this motor? We have a 14' Down River Pro 140, and expect to have a push a couple other boats of similar size.
> 
> Thanks,
> 
> Matt


The guys at DRE are steering you in the right direction. That Honda will work perfect for what you want. I have an older 5 hp Honda that runs like a top and have never had carb issues with it. 

My motor of choice is still my 8hp 2 stroke Johnson Sea Horse. Almost twice the horse power and really not very noticeable between the two when it comes to being noisy. ( they both drown out the radio)

I have really noticed the power difference when it comes to pushing my speedboat. The Honda will barely break 3 knots while the Sea Horse will push it close to 7 knots. The Honda does use a lot less gas, but takes twice as long to get there.


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## chateaunoname

*5, 6, or bigger*

If I had it to do over again, I would probably go with a 6 or 7 HP. Just for a bit more push. Going 3-4 MPH with 3-4 boats against a little wind works fine with me. Quiet and comfortable, not looking to plane out or make a big wake. Any of the known four strokes will be good.


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## Moon

this is my set up, made the transom my self...kinda proud since I don't claim to be a welder... I used 4" channel that I welded at an angle so the motor is fairly straight. I then radius cut the channel to match up to the NRS pipe. Finally I welded tabs on the sides using 3/4" angle and stainless U bolts so I can slide the transom up or down depending on need. I used a single NRS drop rail for the hang over with enough left over for the seat. I bought the seat mount and put a cheap seat from cabelas on it. The prop guard is just flat bar that I bent using a paint can and a vise, not perfectly round but pretty close.... Ive since modified it so its lower than the prop. Last but not least I sold the old Briggs and Straton and just bought New Mercury 6 H.P. 4 stroke long shaft!


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## thinksnow

5-71/2 hp is plenty. Once getting up to 9.9 hp they start to get heavy.


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## mraible

*Leaning toward Tohatsu 6HP*

Thanks to the replies on this thread, I'm leaning toward a 6hp Tohatsu. 

Tohatsu 6hp outboard

I'm thinking it'd be good to get the one with the internal fuel tank, then purchase the external 3.1 gallon tank. That way, there's always a reserve.

Also, y'all seem to suggest a long shaft for a raft. I'm looking to pull the trigger on the ordering tomorrow, so please let me know if a short shaft is better.

Cheers,

Matt


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## oarboatman

If your going to be doing long trips look at the sail pro model. It had a charging coil so you can charge a 12v battery that can then be used to power what ever you need. The 6 hp is great and I have one, but it does not run as quite as the 8 hp because the 6 only has one cylinder.


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## Osprey

Anybody ever tried the propane motors?


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## asleep.at.the.oars

mraible said:


> Also, y'all seem to suggest a long shaft for a raft. I'm looking to pull the trigger on the ordering tomorrow, so please let me know if a short shaft is better.


Where are you going to mount the transom? I measured from the top of my cataraft yoke to the waterline, and it was right at 15", which meant any wave would pull the water intake into the air, so I went for the long shaft. If you drop the motor down, you can save a few pounds & inches though.


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## beware209

mraible said:


> Also, y'all seem to suggest a long shaft for a raft. I'm looking to pull the trigger on the ordering tomorrow, so please let me know if a short shaft is better.


Here are the motors I've owned:
3.5hp Tohatsu 2 stroke
2hp Honda
8hp Honda w/alternator and electric start
6hp Tohatsu
6hp Tohatsu Sail Pro w/alternator
30hp Honda
20hp Tohatsu w/alternator and electric start
18hp Yanmar diesel

If your primary use will be for flat water, my personal favorite is the 2hp Honda. I've used it to push a 16' cat with a 16' SB raft from Flaming Gorge to Lake Powell, used it on the GC, tail end of the San Juan, etc. Here are some of the benefits:

Plastic prop will last for years (you WILL hit a lot of rocks)
1 litre internal tank is good for about 105 minutes
air cooled so no worries about churning up river silt (San Juan)
29 lbs. which over time you will greatly appreciate.

Don't even consider a short shaft. Rafts and cats are considered to be displacement hulls and will only go so fast no matter how much hp you provide meaning 6hp will be only slightly faster than 2hp. However the larger displacement and prop will allow you to push more boats.

Happy motoring. You're going to turn into a lazy boater.


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## MonsterSlayer

Leave the motor at home!


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## beware209

MonsterSlayer said:


> Leave the motor at home!


I don't think it's any of your business how others chose to legally use the waterways. There are plenty of excellent reasons for using a motor. On the above mentioned 456 mile Flaming Gorge to Lake Powell trip there were 5 permits involved and I had to be at specific places at very specific times. That trip (23 days) couldn't have happened without a motor. On the above mentioned Grand Canyon trip we had two 18' rafts invert at 209. With the aid of my motor we were able to corral the boats and boaters quickly into an eddy. 2 injured boaters were then rapidly transported to Diamond Creek for a helicopter evacuation. Just last year a veteran GC boater was killed there when she was in the water too long. On the same trip I broke 2 ribs on day 4. I couldn't have completed the trip without the trusty little Honda.

If all you do are day trips these concepts may be foreign to you.


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## Bigdrops

*Yamaha*

Yamaha is what you want. and Yes you can store it cob side down no problem.


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## thinksnow

beware209 said:


> I don't think it's any of your business how others chose to legally use the waterways. There are plenty of excellent reasons for using a motor. On the above mentioned 456 mile Flaming Gorge to Lake Powell trip there were 5 permits involved and I had to be at specific places at very specific times. That trip (23 days) couldn't have happened without a motor. On the above mentioned Grand Canyon trip we had two 18' rafts invert at 209. With the aid of my motor we were able to corral the boats and boaters quickly into an eddy. 2 injured boaters were then rapidly transported to Diamond Creek for a helicopter evacuation. Just last year a veteran GC boater was killed there when she was in the water too long. On the same trip I broke 2 ribs on day 4. I couldn't have completed the trip without the trusty little Honda.
> 
> If all you do are day trips these concepts may be foreign to you.


nice


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## Bigdrops

Yamaha Long Shaft!



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## Moon

well said beware 209......well said....


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