# 4hp outboard motor questions



## jboat73 (Jun 7, 2012)

Hello,

I'm in the process of buying a 19ft daysailor. I have some sailing experience (ASA 101 plus a bunch of charters), but this is my first owned boat. 

I have some questions on a motor. I'm going to (at least initially) be sailing in a tidal river. I'm getting a slip to reduce the time of getting ready to sail. I expect my windows of time for sailing will only be a few hours, so I want to spend as much of that sailing as I can.

I'm thinking of getting a Tohatsu 4 stroke, 4 hp, regular shaft (15") outboard with a 0.3 gallon integrated fuel tank. Tohatsu because it gets good reviews for reliability and cost. 4 hp because I expect I'll make mistakes on the tide tabels and need to motor home against the current. While the 4hp is heavier (58 lbs) than the smaller engines, because the boat will be in a slip, I think that takes care of the issue of hauling it on and off more frequently. I also want to get a new engine because it is my first boat, and I don't have experience fixing engines, so hopefully it will give me more reliability.

I don't have any sense on how far a 0.3 gallon tank will take me. Do people just carry some extra fuel in an external tank and refill the engine if needed? It seems that for the smaller daysailors, people generally aren't connecting the outboard to an external tank (and I'm not interested in doing that either). Any rules of thumb on how far 0.3 gallon of fuel will take a 19ft daysailor, against some current and maybe some chop?

Generally, is there a different motor I should be looking at? I started with Honda's, but they don't seem to make a 4hp, and are more expensive. It goes from 2hp to 5hp, and for the reasons above, I want more than 2hp. The boat says the max is 4 hp. Nissan and Mercury are the same as Tohatsu at this size. Suzuki and Yamaha's closest dealer was much further away.

Many thanks in advance for any advice.


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## RichH (Jul 10, 2000)

The only difference between the Tohatsu (and private branded Totatsu) 4 & 6 Hp is the carburetor. Suggest you consider the 6hp, which only 'lightly higher' in price and with a lot more maximum output ... you dont 'have to' run at max. output. 

As to reliability, the Tothatsu (as well as most recent 4 strokers) will easily foul the carburetor when ethanolated gasoline is used. To keep the carb. clean ... always run the engine 'dry' (just shut off the fuel supply and let the engine stall), use a stabilizer in the fuel AND drain the fuel and use it in your automobile when the fuel becomes older than 30-45 days. 

Fuel economy depends also on wind and wave conditions and how much power is needed to 'punch through'. In flat water, running below 'flat out', youll probably use ~1/2 gallon per hour with the 6. Consider a remote tank.

There are very good prices for Tohatsu OBs on the internet, and usually include free shipping ... and tax advantages from buying on the 'net' when the supplier is in a different state.


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## chucklesR (Sep 17, 2007)

Most outboards run a roughly the same efficiency rating, plus minus enough to make marketing departments go crazy.

That 1/3 of a tank will run you about an hour. 
That 4 hp will push you at roughly hull speed in a 19 footer (5kts just to do the math easier).
Figure on keeping a 1 gallon tank aboard if that's not enough.


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## caberg (Jul 26, 2012)

Looks like you can expect less than an hour from your 0.3 gal tank: Tohatsu Outboards: Estimated Fuel Consumption for Tohatsu Outboard Motors

If you plan to fill it up before leaving the dock each day, and only plan to motor in and out of the slip, might be a good option for you.

Personally, I wouldn't like the idea of carrying spare fuel and trying to fill up an internal tank on a motor, hanging over the water, while drifting.... (Not even sure that's legal on some waterways due to environmental concerns.)

If you can fit a 5-6 gallon tank somewhere, the convenience factor of not having to routinely mess around with fuel might be enticing.


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## dabnis (Jul 29, 2007)

We have the Tohatsu 6HP and just use the integral tank on our fishing boat. The 4HP & 6HP weigh the same and agree with Rich H that some day in real nasty conditions the extra power may be appreciated. We generally troll for about 3 hours with a 15 minute flat out run back to the ramp and use a little less than a pint of fuel for the day. We are very satisfied with the motor, it runs perfectly. We bought it on the internet, delivered to our door, well packaged in the original container for just over $1,600 total cost. I carry some extra fuel in one pint cans and although I have not re-fueled on the water it is very easy to re-fuel on the driveway from the small container. Make sure the short shaft is long enough for rough, choppy conditions.

Paul T


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## sevseasail (Jan 15, 2007)

RichH said:


> The only difference between the Tohatsu (and private branded Totatsu) 4 & 6 Hp is the carburetor. Suggest you consider the 6hp, which only 'lightly higher' in price and with a lot more maximum output ... you dont 'have to' run at max. output.
> 
> As to reliability, the Tothatsu (as well as most recent 4 strokers) will easily foul the carburetor when ethanolated gasoline is used. To keep the carb. clean ... always run the engine 'dry' (just shut off the fuel supply and let the engine stall), use a stabilizer in the fuel AND drain the fuel and use it in your automobile when the fuel becomes older than 30-45 days.
> 
> ...


+1 on that



caberg said:


> Looks like you can expect less than an hour from your 0.3 gal tank: Tohatsu Outboards: Estimated Fuel Consumption for Tohatsu Outboard Motors
> 
> If you plan to fill it up before leaving the dock each day, and only plan to motor in and out of the slip, might be a good option for you.
> 
> ...


+ 1 on that also.

Here my 2 cents.
I have a catalina 22 and I run a 4 hp (mercury) at half throttle I can cruise at 6Knts (oddly over hull speed) . but I'm in an inland lake with no currents. If I had bad weather and or currents to deal with I would go for the 6HP. 
As far as the integral tank, do yourself a favor and buy an external tank, use the integral as "reserve" if you would....
Also, go with the long shaft, trust me on that one...


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## chef2sail (Nov 27, 2007)

We have the 4hp Tahatsu to power our Walker bay Odessey on Davits. It has plenty of power to put it on a plane and also runs whishper quiet. Oour has an internal tank and also an attachment for an external tank. It is the lowest hp model 4 stroke which has this dfeature. W have a snall 3 gallon Moeller tank in the dinghy. We get many miles/ hours on the external tank and about 1 hour on the internal. 

When we turn off the engine we discinnect the external and let the engine run out of gas thus emptying the carborator as well as fuel lines, when we are using ethanlo,based gases as the varnish tends to build in the carb if left there. We use aviation fuel when possible so there is no problem with varnish.

Dave


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## Sunday Driver (Oct 25, 2011)

I would go for the 6 hp too ,its the same weight .
its not a big deal till you need it ...

we have the Tohatsu 6 and are very happy with it ..couple years old and no problems so far


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## SHNOOL (Jun 7, 2007)

I'm going to buck the trend, and say get a nicely cared for used 2 stroke and go smaller in size. 4hp for a 19 foot boat is overkill. I use a 2.2hp for my 25 footer, and it pushes me to 5.2 knots (hull speed on flat water). Granted, a 4hp is probably better for my boat. But the 2.2 runs well.

The tohatsu are the same as the merc, and 3 other motors. they make them all. Great motors and you can't go wrong. What these guys are saying is it's better to go bigger than you need (and I agree), I think 4hp IS bigger than you need.

That being said, they are also right in that the 6hp is the same weight (too much mind you) as the 4hp so if you are OK with the 4hp weight, then then 6hp is OK.

Have you considered HONDA? Their 3.5 is really nice (pricey) but a real steal, and also quite light.

My 2.2hp 2 stroke merc, runs for about 2 straight hours on a full (integrated 1 liter) tank of fuel. I carry extra fuel in a Jerry Can but I DON'T leave it on the boat. My boat doesn't have a dedicated fuel locker, so the tank doesn't stay (unless I forget - which I did last night).


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## tommays (Sep 9, 2008)

You do need the long shaft and the 25" on the 6 HP is great

BUT there is really ONLY one good High Thrust Porp which the 4 HP motor has NO problem reaching FULL RPM with SO i have never really figured out how you would deliver the extra 2 HP ?

As i have never had and issue moving even the 8000# boat or the J24 in 30 knots ?


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## Barquito (Dec 5, 2007)

Having an extra 5 gal. tank stored up front might help balance the motor hanging on the stern.


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## dabnis (Jul 29, 2007)

tommays said:


> You do need the long shaft and the 25" on the 6 HP is great
> 
> BUT there is really ONLY one good High Thrust Porp which the 4 HP motor has NO problem reaching FULL RPM with SO i have never really figured out how you would deliver the extra 2 HP ?
> 
> As i have never had and issue moving even the 8000# boat or the J24 in 30 knots ?


The 6HP makes 500 more RPM

Tohatsu 4hp Four-Stroke Outboard Model # MFS4CDS

Paul T


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## dabnis (Jul 29, 2007)

dabnis said:


> We have the Tohatsu 6HP and just use the integral tank on our fishing boat. The 4HP & 6HP weigh the same and agree with Rich H that some day in real nasty conditions the extra power may be appreciated. We generally troll for about 3 hours with a 15 minute flat out run back to the ramp and use a little less than a pint of fuel for the day. We are very satisfied with the motor, it runs perfectly. We bought it on the internet, delivered to our door, well packaged in the original container for just over $1,600 total cost. I carry some extra fuel in one pint cans and although I have not re-fueled on the water it is very easy to re-fuel on the driveway from the small container. Make sure the short shaft is long enough for rough, choppy conditions.
> 
> Paul T


Made a mistake, the price was about $1,300

Tohatsu Outboard Motor 6hp 4-Stroke

Paul T


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## ShoalFinder (May 18, 2012)

I am running a Nissan 5HP (which is now Tohatsu) on my Morgan 22. It's a 2 stroke with the integral tank. My Morgan 22 is probably the heaviest 22ft boat you'll ever see. The Nissan 5 pushes the boat through the marina at idle and I cruise at half throttle. 

I personally love the integral tank. After years of powerboating, not having a fuel line hung over the transom going to a stinky tank with 2 cycle oil residue on it is wonderful.

I take along a spare gas can, which nowadays all them have the locking spout. It works great. You hang the nub of the pour spout on the lip of the tank opening and then you twist the lock on the spout to start filling the tank. When you lift the gas can the spout closes. No muss, no fuss, no spills. And that's filling the outboard while I lean over the transom. 

Mine is not the long shaft. I would trade mine for a long shaft in a skinny minute. When motoring in swells over 3ft, the prop often comes out of the water and the engine over-revs. I have to mind the throttle to get the RPMs back down which is a pain.

If I ever have to replace my little Nissan 5 I'll probably buy another one just like it with a long shaft.


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## SHNOOL (Jun 7, 2007)

I guess it is just me then, cause I went to the short shaft , because the long shaft wouldn't clear the water! It depends how low the motor mount is.


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## rightbrainer (Jul 28, 2011)

I had a short shaft, no gears(start and go), two stroke on a Santana 20. I replaced it with a 4hp long shaft twin cylinder N-F Evinrude. Some things I learned from the experience: 1) with the short shaft, the prop & water intake came out of the water if I went forward...not good; 2) one-lung engines vibrate a lot more than two cylinder engines. A fiberglass boat is a giant resonator. 3) Not having neutral and reverse makes for some very exciting moments at the dock, especially if the wind is from an inconvenient direction; 4) An external tank is nice if you have someplace to keep it. Don't forget to close the vent. The internal tank will take you a long way, but one way or the other, you'll need backup gas on-board. 5) Weight counts. 58# is a lot of weight hanging out there on the stern of a 19 footer. It makes your boat slow to not be sailing on her proper lines and most small boats are drag-ass to begin with. Two-strokes tend to be a lot lighter. Happy hunting!

p.s. If you don't carry enough fuel to deal with an unexpected situation, make sure you have good ground tackle!


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## solarfry (Sep 6, 2008)

Anybody that tells you a 2 hp will push you into an inlet in a falling tide is nuts. If you are taking that boat offshore get the 3 gallon auxilliary gas tank. It sucks to run out of fuel at the inlet. If you have to refuel, over 75% of the gas will spill in boat, on water, on your hands, etc. A 4 hp will push you but a 6hp will get you in quicker without having to run it flat out. The 6hp also has a generator kit to charge your bat. Most inlets are narrow with flows in the 3 to 5 mph. Getting inside while going under a bridge is a harrowing experience with motorboaters going every which way at 1o to 12 mph and dragging a 3 to 4' wake. 

Make it a point to disconnect the fuel line and run motor on fresh water muffs until it runs out of gas and conks out. Do not use fuel from Marinas but buy the fuel where you fuel up your car. If the gas is 3 mos old pour it into your automobile fuel tank. Get fresh gas.The day you forget to run the engine dry will be the beginning of problems with it. Disregard the nuts worried about wear on motor. 

The issue is not getting around the Marina. It's getting through a tidal region, under a bridge, usually in a falling tide, against a 20 knot wind with boats of all kind trying to go through at the same time. Most of them dragging a 4' wake behind. I know, I have to face it all the time.


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## INMA (Sep 13, 2011)

I have a 5hp two stroke which has plenty of power for an 850kg yacht.

The 4hp four stroke with long shaft and high thrust propeller will easily do your job but a 6hp longshaft with high thrust propeller and external tank will do your job better.

Any money spent on the bigger outboard will be well spent and leaves you with some extra thrust to push into a bad wind or tow another yacht.

Short shaft engines are not suitable for most displacement hulls.


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## Ulladh (Jul 12, 2007)

jboat is getting a 19ft daysailer, not an offshore boat for crashing through major inlets. A lightweight 4hp is all the boat really needs. Tohatsu makes 3.5hp motors that would be sufficient for a lightweight daysailer.

Larger heavier motors would add excessive weight to the stern without producing any additional speed.

All the boat needs is enough power to produce modest progress against a tidal current.

Jboat, I think is getting a Flyingscot, these boats are lightweight and fly in the gentlest breeze on the Delaware river, and are less effected by the currents than a full keel or deep keel boat. 

With more experience this is a boat that can be used on the river without a motor.


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## Florida Sailor (Aug 21, 2012)

I bought a slightly used, Nissan 3.5hp two-stroke for my Oday Daysailer. Fuel consumption is spec'd at 1.7 liters per hour at full throttle and I find that to be accurate. Motor has an integral tank that holds 1.4 liters. Weight is 28 pounds. +1 on going with a long shaft motor. More than enough hp for my boat.


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## ShoalFinder (May 18, 2012)

Forgive me if these things have already been stated, but a few things to narrow your search:


2 stroke is a pain in that you have to mix oil with the gas. That means you need to keep 2 stroke oil on hand.

2 stroke motor is lighter for the same HP than a 4 stroke will be.

2 stroke motor can be laid down on its side without oil running out of the motor and all over the place. 4 stroke usually cannot.

4 stroke motor is more complex (valves, timing, etc.) 2 stroke is pretty bare bones design.

2 strokes can be a serious PITA- they hate stale gas, they tend to be cold natured, carb filter / fuel pump filter (side of carb) gets dirty quicker. Spark plug gets fouled when your mixture gets off, then the *$%^* thing won't start or won't run under load.

2 stroke can't be left sitting with gas in it for long periods of time. The gas turns to Aunt Jemima syrup in your carb. As I said, you'll get good at carb work with a 2 stroke. 

DO NOT run ethanol gas in your 2 stroke. You can get away with it at times, but you'll spend a lot of time cussing your motor for running badly / choking out with no good explanation. Ethanol is the debbil! These little motors also run rubber fuel hoses. Ethanol eats those.


If you are mechanically handy, a 2 stroke can be had on the cheap but like any 2 stroke you'll spend time wrenching on it. You'll get good at doing carbs. If you one day end up with a gasoline generator, now you'll have to tote around two separate gas cans if your kicker is a 2 stroke. With a 4 stroke they can share gas.


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## Florida Sailor (Aug 21, 2012)

I guess I've been lucky with my 2 stroke as I haven't experienced any of the previously mentioned problems (knock on wood). Mine always starts on the 1st or 2nd pull. The only time I had to restart the motor was when I was too slow opening the choke. It usually has old gas (I don't use much) and I've never cleaned or changed the spark plug. I do run the carb out of fuel after each use however.


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## ahab211 (Jan 6, 2008)

I understand that Tohatsu bought Merc, make a well equipped, comparable, much cheaper motor. Why buy a Merc when a Tohatsu as my friend who sold his Merc to buy one says the best motor he ever had!


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## TakeFive (Oct 22, 2009)

jboat73 - Since you are getting your boat directly from the manufacturer, I'd suggest you ask them for a recommendation about motor size. Describe where you're sailing.

Many of the boats that are being referenced here are pocket cruisers, which are much heavier than your Flying Scot. As Ulladh said, many use the Flying Scot without any motor at all, and keep a couple paddles for emergency. The one I rented had no motor, and we rented it on a dead day.

I see some guys talking about getting a motor with an alternator to charge your battery, etc. They definitely don't understand your boat. You'll need to filter some of the recommendations based on how well you think the posters understand your boat and sailing range.

For what it's worth, I think it's likely that 2 hp is enough to get you wherever you will need to go, even against the Delaware's tidal current. It's a small boat with very little draft. Most of the guys recommending 4-6 hp are sailing much heavier boats than yours.

The capacity plate says 4 HP, but that's the maximum. (And I question whether you need this much.) For this reason, I wouldn't go over 4 HP, even if the 6 HP motor is a "twin." If you ever get pulled over by law enforcement, you may get some tough questioning about exceeding the boat's rated capacity. And the rating is about more than just dead weight - it's about what can go wrong if you accidentally throttle up too high (like swamping the boat).

Light weight is a benefit for boat trim, even if you don't care about removing the motor every time. Since it's off-center, you want to minimize the boat's list, especially since you're keeping it in a slip. And if it ever needs service, you'll be glad you have lighter weight so you can pull the motor instead of the whole boat.

I read somewhere the Suzuki makes the lightest 2.5 hp motor. I've seen online specials for under $700:

2012 SUZUKI 2.5HP OUTBOARD MOTOR

Suzuki Outboards 2.5 Horsepower

But if you're going to buy in this size range, I'd consider an extra $140 for the air cooled 2 hp Honda. Actually its weight looks exactly the same as the Suzuki. Note that Honda has 2 shaft lengths in this size, and you should probably get the longer shaft:

Honda BF2DKLCH Outboard Motor (Four Stroke) - Price: $838.08

One critical thing to look at is how whatever motor you pick can be locked to the transom. This is critically important if you're keeping it in a slip, especially if you're considering downtown Philly.


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## overbored (Oct 8, 2010)

if the 19 footer is a flying scot then 2 hp is plenty 4 hp and it might even get up on a plane. what you want is the lightest thing out there. I used to have a scot with a 1.5 British seagull and we had a speed boat, would go over 5 kts all day when we could get it started


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## TakeFive (Oct 22, 2009)

FYI, if the Tohatsu is only available in a 15" shaft length, then that could tip the balance strongly in favor of the Honda, which shows a 20" shaft length in the link I posted above. While your transom may be only 15" high, you want the prop immersed well underwater so you can motor through chop and also if you're heeled over. Even under bare poles, in a heavy blow your boat could heel over and you want the prop underwater in those conditions.

If the Tohatsu is available in 20" length, then I'd consider that over 15".

By the way, the Honda at boats.net (which I linked) is significantly discounted (35% off MSRP).


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## jboat73 (Jun 7, 2012)

Thank you to everyone that has chimed in; I appreciate all the advice.

The boat is indeed a Flying Scot. The manufacturer says the max is 4hp. I think many owners don't put a motor on at all, but I believe that some of those may be sailing on lakes, so no tide issues. Maybe I'll get to a stage of having enough skill and confidence to have no motor, but right now I really want the comfort of knowing a motor is there to help if needed.

The manufacturer has also said to get the shorter shaft, but what people are saying here about the longer shaft makes a lot of sense to me. Is a longer shaft an issue if the boat sits low and you're in shallow water? I'll inquire about that.

Is it fair to say that Honday 2hp would be lower maintenance than a Tohatsu 4hp? I don't have experience with engines and lower maintenance is definitely appealing. But I'm balancing that against more horses and therefore more ability to get me home after I've screwed up and found myself fighting the tide! Also, in a short sailing window, I think it is inevitable that I'll need to fight the tide one way or the other if I'm not going at slack tide or timing my turn-around with the tide reversal.

Thanks again.


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## jboat73 (Jun 7, 2012)

I think I've just ruled out the Honda 2 hp - it doesn't have reverse. It has a swivel mechanism and has to be turned around to go in reverse. I imagine for someone with experience that isn't a big deal, but for me, the difficulty of docking doesn't need the added issue of swinging the motor around!


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## Sal Paradise (Sep 14, 2012)

Hi ,

I have the Tohatsu/Merc 4HP on my Catalina 22, in the Hudson River which is seriously tidal. The motor is enough for my boat against the tide and even wind. 

They are notorious for plugging up the carbs with ethanol gas. Its easy to take the carb apart. Other than that repetitive problem they are good.

It is true that the 4, 5 and 6 HP are all the exact same but different carbs. Might as well get the 6 in case you get a bigger boat or a dingy.


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## INMA (Sep 13, 2011)

With the new information, consider a long shaft 3.5hp.

Weight is still light enough for a light weight yacht.

Brand is not as important as service so see what local dealers are available.

Tohatsu, Mercury, Suzuki and Yamaha all offer good outboard in this size.


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## dabnis (Jul 29, 2007)

I had the Honda 2HP and now have the Tohatsu 6HP. The Honda weighs 27 lbs the Tohatsu almost 60lbs. Sounds like the Flying Scott is light, my guess is that you could probably get 5 Knots out of it with the 2HP? Long shaft is good regardless of motor. The gear shift is easier than the 180 reverse but that is a big weight difference. My 2HP Honda was a good bullet proof motor, ran it hard for over 20 years, still ran perfectly when I sold it.

Paul T


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## TakeFive (Oct 22, 2009)

jboat73 said:


> I think I've just ruled out the Honda 2 hp - it doesn't have reverse. It has a swivel mechanism and has to be turned around to go in reverse. I imagine for someone with experience that isn't a big deal, but for me, the difficulty of docking doesn't need the added issue of swinging the motor around!


I had a similar motor when I was 12 years old (no neutral or reverse, but a 360 degree swivel with a handle that flipped backwards) and I had no problem figuring it out at that age. That motor had no clutch at all - the prop was always spinning, and it still worked fine. I think (but you should verify) that the Honda has a centrifugal clutch that disengages the prop at low RPM, which is a little more user friendly than the one I had.

If you feel more confident with 4 hp and really want a reverse gear, that's fine. I certainly don't want to push you into getting a motor that you might be unhappy with.

However, let me make a couple of final points. First, I wasn't suggesting that you should go motorless with paddles. With small kids on the boat you need a motor. I just meant to imply that 2 hp is much more thrust than you would get with paddles, so 2 hp should be adequate for this boat. Also, someone else here already pointed out that he could get 5 knots out of a 1.5 hp motor on his former Flying Scot, more evidence that 2 hp may be all you need.

Finally, one last consideration. I have not owned any of these small motors (as you know, I have a 15 hp Honda on my boat), so I have no personal knowledge of their reliability. I expect Tohatsu or Honda to be low maintenance. But the Honda has air cooling and no reverse, eliminating the water pump/impeller and shift mechanism, which are two maintenance items. Since you had asked about reliability and maintenance, the simplicity of Honda's design would be a plus.

In the end you need to get what you're comfortable with. You'll get no complaints from me if you go bigger than 2 hp. When I was shopping for boats I frustrated several people because I didn't follow their advice, but I'm happy I made the decisions that I made. As you're undoubtedly experiencing now, when you get so much conflicting advice it's impossible to follow it all. So good luck with whatever you do.

EDIT: One last thing. I have an inflatable rowing dinghy that I've never used (see my avatar pic). If I ever start using it regularly enough to need a motor, I'd get the Honda 2 hp in a heartbeat.


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## Marcel D (Apr 15, 2012)

I had a 4hp yamaha 2 stroke worked great always started. Good engin nice and strong pushed a 24 foot boat tob 5.4 knots threw the water. she had an internal tank that lasted 2 hours.


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