5-10hp 2-stroke vs 4-stroke

[SKMT]

Originally Posted by RiverRat37

Really? A 60HP on a 14' skiff? Have you checked the label on the boat for its maximum HP rating? I watched in horror as an overpowered outboard lurched upside down killing the two parents -- the two kids were wearing PFDs and we were able to rescue them but they became orphans in a moment. The boat had 20HP too much whilst the wife pushed the throttle forward with the helm hard over. The transom went down hard whilst the bow went up fast. That overpowering ended their lives. 60 on a 14 sounds like trouble to me.

Yeah well you're opening your mouth a little too wide...I know what my boat needs

[SKMT]

Looks like absolutely no consensus. Thanks for the input though!

[Cheechako]

If you are not getting enough HP to plane, then no point in buying more than 4-6 HP. Are you sure she can reliably start an outboard?
Is it a short distance? I wonder if a good electric OB would be better for her?

[SKMT]

Originally Posted by Cheechako

If you are not getting enough HP to plane, then no point in buying more than 4-6 HP. Are you sure she can reliably start an outboard?
Is it a short distance? I wonder if a good electric OB would be better for her?

It get's rough where I anchor. I need something with at least enough power to get the bow up...but riding on top of waves on plane would be ideal.

I see Saturn sells a 11ft inflstable catamaran (looks like Takacat knockoff) that supposedly can plane with a 6hp. But i don't think i would trust her with that boat because it looks like it could become a kite. Also I'm strongly prejudiced against inflatables (and pvc in particular), but as a 2nd dinghy it seems like i might have to go that direction.

[boatpoker]

Originally Posted by SKMT

I know nothing about small outboards (my tender is a 14ft fiberglass skiff with a 60hp). My gf moved on my boat and is gonna start back working soon. I want to get a little auxiliary dinghy for her so I don't have to ferry her back and forth to shore 5 days a week.

Obviously new 2 strokes are banned in the US...but still can be found used. They are lighter...and the outboard will have to come off the dinghy whenever I move the mothership (which is just occasional). Is there a consensus preference amongst cruisers on 4-stroke vs 2-stroke in the 5-10hp size range?

2-stroke Suzuki with oil injection. No mixing fuel/oil and the most reliable motor I have ever owned.

[Dockhead]

Originally Posted by Robhwa

If low weight and reliability is critical, cost isn't so much a factor, and distances are relative short (<5 miles), consider an electric. I have two Torqeedos for my kayak and dinghy, and even use a Minnkota 80 lb thrust as my trolling and backup motor on my 22 ft C-Dory. The Torqeedo outboard I have weighs about 20 lb total, but I clamp the motor shaft on first, about half that weight, then put the battery on it, so I never lift more than about 10 lbs. Easy for an aging mariner. No fuel, no oil, no pulling to start, and it can be stored upright, on its side, or upside down. Theft of an outboard hanging off the back of your main boat is a serious problem in some places. I lock the Torqeedo away. Charging can be solar or from the house batteries. Expensive, though, and some people have had reliability issues. I have had none over 5 years. Frankly, I am sold. For longer distances you need a gasoline motor.

Over the last 12 years I have gone from 25hp to 8hp to 3.5hp, and since I can't plane the dink with 3.5hp I realize I might as well have gone with the Torqueedo. Disadvantages cost and range, but the other advantages -- which you well described -- are overwhelming for many use cases, like mine. Could be a good solution for the OP.

[SKMT]

Originally Posted by mvmojo

What about one of the propane outboards?

I actually have a 5hp Lehr that came with my trawler. I have been meaning to sell it for 2 years. All I see is disadvantages with propane outboards. To it's credit, it does start right up even though it never gets used. If anybody in South Florida wants one, let me know.

[sv Stella Maris]

2 stoke always when under 30hp for outboards. I’ve owned, maintained, overhauled and raced with both types.

Under 30-40hp the carb components are very fickle and clog easily. Also, tolerances on small engines don’t allow for the sloppy reality of poor environments as well. 2 strokes really shine in this department.

Half the parts equals half the trouble. Premix is a mute point. Read the manual. Always race your engine before shutoff. And run ANY carb dry before a week of inactivity. And fuel stabilizer for an infrequently used engine.

Good luck.

[CAVOK]

For your girlfriends sake
1. Make sure she can pull start the engine. My wife has difficulty with our Honda 6hp. We had a Suzuki 2.3 which was easier, but could still have a nasty little kickback if not pulled hard.
2. If money (& speed) isn’t a problem I’d advise an electric outboard (Torqueedo or E-propulsion) We are about to get one and sell our Honda. Just too hard to lift on and off our live aboard.

[David Mathis]

Our 9.9 1985 Evinrude we use to push the 10' inflatable ran great until it started hard last year. The carburetor was rebuilt, now it's ready for another 37 years. As to pollution, lets get real; in an entire year it probably burns less fuel and pollutes less than a large yacht coming into the harbor and docking. It pulls the grand kids on a knee board and transports the guests and us to islands and shore. It's perfect, but unfortunately long out of production. Several times a year someone will ask if we will sell it. We have no desire to replace it with a newer four stroke even though they're quieter and burn less fuel.

[skipgundlach]

Originally Posted by Jammer

The last 2-strokes in that hp range in the USA
were sold in 2006.


So in practice the question is whether you would rather have a 15+
year old 2-stroke or a newer 4-stroke. You can get older 3 (+/-) hp
motors that haven't been run much but many (most?) 10 hp+ motors that
old have been run regularly and by 15 or 20 years old are due for
things like new cylinders just because of hours.


2 stroke is lighter because there's no valve train, and can be stored
in any orientation without entering hydraulic lock.



4 stroke will get significantly better fuel economy (in distance
per gallon terms, about 50% at WOT and 100% at idle) and will operate
at idle/trolling speed for longer without fouling the spark plugs.
The fuel economy improvement means that you can use a 3 gallon tank
where you would use a 6 gallon tank for a 2 stroke; you're carrying 15
pounds less fuel which makes up in a sense for the weight of the valve
train. You will pollute less mainly because of drastically reduced
amounts of unburned fuel in the exhaust. You will change one quart of
oil every 100 hours rather than adding one quart of oil to the gas
every 10 hours. Engine longevity is somewhat greater though this is
hard to quantify as small outboards are discarded for many reasons
other than wear and most do not have hour meters.


In practice either will push the boat

WHAT???

Even my ancient Evinrude 6 and Johnson 15 only use 50-1 mix. A quart
will do 12.5G of mix. How BIG is your fuel tank??? How much fuel
does it have to eat to make that last only 10 hours??? (Data Point;
daily use to the dinghy dock ~10 minutes each way lasts us about 3 -
~30 hours - months in a 6G container)

As I don't have a 4-stroke (oil changes are the bane of my life; two
engines - one each diesel and 4-stroke Honda 2200i - is more than
enough) I can't verify the numbers about fuel efficiency, but I find
your numbers astounding.

As to other concerns about ethanol, at least in the US, most marinas
will sell ethanol free gasoline only.

Yes you can buy your gasoline much less expensively at a discount
drive-up, but, like the old ads, pay me now or pay me later, if you
don't go to the equally expensive 100% gasoline station pump, it's a
recipe for later dissatisfaction. So, just fill the 2-strokes'
can(s - see below) as needed.

Our solution for partial tanks is to have two. When one gets
empty-ish, we drain it into the other empty-ish can, load a pint of
oil, and take it to the gas dock, where we fill it with 6.2G of
unleaded fuel (Valvetec brand in most US marinas).

Because it's altogether full, and our seals aren't perfect, we decant
about a gallon into the now-not-empty fuel can. We use the almost
empty (~2G or so) until it coughs under way, adjust it to get more
fuel and swap tanks when we get back to the boat.

Rinse, repeat, so to speak.

As to the girlfriend boat, I recommend a PortaBote. 8' would be
adequate to her needs, and it will plane easily with a 4-ish HP. A
10' will plane easily with 6HP, 2-up (we two and dive gear and fuel =
~400#) and is our preferred dive boat (easy re-entry over the bow; see
other posts with me and PortaBote in the search). Stows folded about
the same size as a surfboard or small SUP, with seats and hardware in
a duffel. ~15 knots in the 10' mentioned above, and we can go for a
dive 5 miles away without thinking much about it, the PB being far
more efficient than the RIB cited above in fuel consumption.

In the case of our (now sold; black marks on white hull finally killed
it) gone PB, the engine was a 20 YO Evinrude 6HP. The 8HP weighs the
same, if you can find one, and will take that bote and 400 pounds
payload at close to 20 knots if you wanted. We've taken ours in 6'
(not breaking) seas in extremely remote locations confidently. If it
weren't for the marking, there's NO way I'd have let it off the
boat...

Sorry - that wasn't really the question asked, but...

And, you can buy 2-strokes everywhere else in the world; a quick trip
to the Bahamas will set you right up

[timb7734]

Later model Yamaha with oil injection, no smoke as the oil is measured exact, no oily film, less maintenance as no oil changes, and except at low speeds, close enough on the fuel mileage, at a lighter weight per horsepower, and smaller profile.

[Rough Magic]

My experience is that women really hate the stink of the 2 strokes. To say nothing of the odor getting in her clothes, hair, on the way to the dock for work. I've got a Honda 2.2 hp 4 stroke. Easy to start, light weight. Vibrates a bit and a little noisy. Great little engine.

[Dockhead]

Originally Posted by Rough Magic

My experience is that women really hate the stink of the 2 strokes. To say nothing of the odor getting in her clothes, hair, on the way to the dock for work. I've got a Honda 2.2 hp 4 stroke. Easy to start, light weight. Vibrates a bit and a little noisy. Great little engine.

Ah, the smell of two stroke exhaust in the morning . . . it smells like . . . victory.


I LOVE the smell of operating two stroke engines. Some of my earliest memories are of my father taking me out on a boat with a two stroke outboard. Never met a woman who disliked it, either.

[Robhwa]

Originally Posted by Dockhead

Ah, the smell of two stroke exhaust in the morning . . . it smells like . . . victory.


I LOVE the smell of operating two stroke engines. Some of my earliest memories are of my father taking me out on a boat with a two stroke outboard. Never met a woman who disliked it, either.

Memories, memories. I used to think the same, and the smell of my father's cigarettes on the Chesapeake Bay gave me a nostalgic field as well. Kind of like Pavlov's dog, I guess.

After years of not smoking and rarely using any of my 4 small two stroke motors (only the weed trimmer now), I'd rather not be breathing any combustion products. Running the electric motors while trolling for salmon and being able to pick up marine scents rather than outboard exhaust is much better, IMHO, but that is just my opinion. I do understand the nostalgia of exhaust scents.