2 stroke vs 4

[hberg]

Here in the PRC (California), it’s electric or 4 stroke. I’m good with that. But a small 4 stroke has a carb and that means our ethanol laced fuel will screw it up in about two weeks time if left in the engine. So I would advise trying to live with the shortcomings of electric if you come down here. Final consideration; what’s the largest and heaviest motor you can lift on or off you dinghy to the stern rail mount while rocking around at anchor? For me the six is the absolute limit.

Cost of electric hasnt led us to really consider it... by from that pt come power issues for us on solar mainly, not having a generator, and all the other issues raised here.

Thanks for the pt about consideration of rocking at anchor, one I hadn't thought about. 6hp 4 stroke so about 60 lbs there? You use a halyard?

 

[hberg]

If cruising to any degree, one will find that the very low powered propulsion devices will become problematic.

Not all harbors are nearby, calm and have provision near. And some people spearfish and explore which can take miles of distance. And catch crap weather or just plain winter trades.

It was my experience that the 8hp would not get on plane if we had a load. That made for some let’s say less than optimal forays.

F.ex: Caught a squall coming back to the boat one day, that would have been frankly nightmarish if we had been carrying a provision load.

Preferred anchorages would by necessity not be remote, or else bound to take the mothership in at great inconvenience, and two bigger diesels chugging away. I have no trouble finding 2-stroke oil, but I bet finding parts for an electric motor will be expensive to impossible. For the weight, no electric that I know of will have the ass to get me through weather.

The general wisdom seems to be ‘get the biggest dinghy you can,’ but I think I’ve found my best happy medium. Bear in mind, people on islands use outboards, you know. YMMV

View attachment 536460

Thanks for the response! The uograded dinghy search has commenced. This makes me think about the fact that we physically won't be making it in our boat many places due to a 7' draft so a beefy dink set up to see "cool stuff" will be more than necessary if that's to be the goal, alongside safety and such

We inherited an ancient 20lb thrust sears outboard - tried it out on a calm August day. Took 30 minutes to get where I can go 7 min by paddle and killed the extra battery we had lying around....albeit far from the current electric OBs capabilities your comment reminds of it

 

[seaker]

Thanks for the response! The uograded dinghy search has commenced. This makes me think about the fact that we physically won't be making it in our boat many places due to a 7' draft so a beefy dink set up to see "cool stuff" will be more than necessary if that's to be the goal, alongside safety and such

We inherited an ancient 20lb thrust sears outboard - tried it out on a calm August day. Took 30 minutes to get where I can go 7 min by paddle and killed the extra battery we had lying around....albeit far from the current electric OBs capabilities your comment reminds of it

20 lbs is a very small electric these days. And if it was a battery you had, was it a good battery and was it fully charged. So not really a good test for you.

 

[Max Rockatansky]

Another consideration if going further afield is something briefly mentioned above but I'll reiterate.

You may well need to use your dinghy as an auxiliary to the mother ship. Or, as we did for a neighbor, use the dinghy to pull the mother ship out from being stuck. Those 15 horses of mine and blue smoke were gratefully welcomed by that fellow on that day, you may believe

 

[Ajax]

Another consideration if going further afield is something briefly mentioned above but I'll reiterate.

You may well need to use your dinghy as an auxiliary to the mother ship. Or, as we did for a neighbor, use the dinghy to pull the mother ship out from being stuck. Those 15 horses of mine and blue smoke were gratefully welcomed by that fellow on that day, you may believe

I agree that there's value in being able to bow or hip-tow your boat with the dinghy but many of us don't own motherships large enough to allow us to carry a dinghy capable of sporting 15hp.

My boat is 33'8". Carrying a 9' dinghy is a real stretch for me and the max allowed HP is like, 5hp. Faced with these limitations it really doesn't matter if I go petrol or electric, it's just a question of whether I want the longer range that petrol offers or the ability to "make" fuel from sunlight that electric offers.

Ya know, I'm still looking for that "silver bullet" dinghy solution but I haven't found it yet.

I love my rigid Dyer 9' but I'm really shy about using it on long coastal cruises. I love it for around the Chesapeake.
I prefer my Achilles 9' inflatable for the long cruises because it deflates and stows compactly.

I may end up purchasing a 2hp gas outboard if I know I'm doing something that electric propulsion just isn't good for.

 

[MarkY]

Hello! We cruise in the PNW but am planning to go further afield in the next year or so and need a new outboard on the dinghy. Looking at pros/cons for 2 stroke versus 4. The make will probably be Tohatsu/Nissan/Mercury and looking for 5-9 hp. Price/condition are really the only factors aside from 2 vs 4. The lower weight is attractive for 2 strokes as for the same 60lbs weight we could get an 8hp in place of a 4 or 5hp 4 stroke.

For the cruisers out there - has one stood out over the other as being easier to fix while cruising outside of the US? Is it particularly annoying dealing with mixed fuel?

And emissions. It seems well known that 2 strokes produce more (quantity) harmful emissions, due to mixed fuel so oil is being burnt/expelled & also the frequency gas is added in the fuel cycle. This is true for large outboards I'm obviously convinced but it so bad for these little 6hp outboards as well? Or do they turn out to be about the same? Can't find any distinctions online.

Thanks for your input!

My experience with small 4 strokes has not been good in terms of working on them. The carbs are finicky, and if I were going abroad or a long distance, I would carry a spare, along with a fuel pump. 2 strokes are more bulletproof IMO, with the benefit of being a lot lighter. Another commenter rightly points out the pollution issue, but with a 6hp, the fuel consumption is so low that the output in the water is very small. Zero is optimum of course, but you have to consider the overall pro/con. For a service dingy, electric might do the trick if cost isn't an issue.

 

[Izzyforreal]

Hello! We cruise in the PNW but am planning to go further afield in the next year or so and need a new outboard on the dinghy. Looking at pros/cons for 2 stroke versus 4. The make will probably be Tohatsu/Nissan/Mercury and looking for 5-9 hp. Price/condition are really the only factors aside from 2 vs 4. The lower weight is attractive for 2 strokes as for the same 60lbs weight we could get an 8hp in place of a 4 or 5hp 4 stroke.

For the cruisers out there - has one stood out over the other as being easier to fix while cruising outside of the US? Is it particularly annoying dealing with mixed fuel?

And emissions. It seems well known that 2 strokes produce more (quantity) harmful emissions, due to mixed fuel so oil is being burnt/expelled & also the frequency gas is added in the fuel cycle. This is true for large outboards I'm obviously convinced but it so bad for these little 6hp outboards as well? Or do they turn out to be about the same? Can't find any distinctions online.

Thanks for your input!

We've got an old Tohatsu 8hp 2 stroke on our 10.5 ft aluminum floored Costco dinghy. I think the dinghy weighs around 135#. That motor will get it up on a plane even with two people aboard. I had it tuned up a couple of years ago, but haven't touched it since then. It gets daily cruising use from late May into October. Runs like a top. The 58 lb. weight is a big plus when getting it on and off the dinghy and onto the stern pulpit.

 

[TWOBOATER]

I work at an outboard boat dealership. Smaller 4-strokes are heavy and hard-starting compared to 2-stroke equivalents. 2 strokes also handle / run better on ethanol fuel than 4s in my experience. I would advise finding a used 2 stroke preferably from a lake area, less apt to corrosion. The weight savings and reliability are worth it. As far as pollution goes, If fuel / oil mix is done properly, (I go light on the oil) smoke and spatter on the water are really minimal.

 

[lom]

I agree that there's value in being able to bow or hip-tow your boat with the dinghy but many of us don't own motherships large enough to allow us to carry a dinghy capable of sporting 15hp.

My boat is 33'8". Carrying a 9' dinghy is a real stretch for me and the max allowed HP is like, 5hp. Faced with these limitations it really doesn't matter if I go petrol or electric, it's just a question of whether I want the longer range that petrol offers or the ability to "make" fuel from sunlight that electric offers.

Ya know, I'm still looking for that "silver bullet" dinghy solution but I haven't found it yet.

I love my rigid Dyer 9' but I'm really shy about using it on long coastal cruises. I love it for around the Chesapeake.
I prefer my Achilles 9' inflatable for the long cruises because it deflates and stows compactly.

I may end up purchasing a 2hp gas outboard if I know I'm doing something that electric propulsion just isn't good for.

Do you have any stays on your newly non-skidded foredeck between the forestay and the mast? Or do you put the dink elsewhere?

 

[lom]

We've got an old Tohatsu 8hp 2 stroke on our 10.5 ft aluminum floored Costco dinghy. I think the dinghy weighs around 135#. That motor will get it up on a plane even with two people aboard. I had it tuned up a couple of years ago, but haven't touched it since then. It gets daily cruising use from late May into October. Runs like a top. The 58 lb. weight is a big plus when getting it on and off the dinghy and onto the stern pulpit.

View attachment 536884

Thanks for the info! That's good to know, we may be going for an 8hp 2 stroke Nissan/Tohatsu and cool to know it gets a larger dink than ours movin'!

Another consideration if going further afield is something briefly mentioned above but I'll reiterate.

You may well need to use your dinghy as an auxiliary to the mother ship. Or, as we did for a neighbor, use the dinghy to pull the mother ship out from being stuck. Those 15 horses of mine and blue smoke were gratefully welcomed by that fellow on that day, you may believe

That makes a lot of sense, we have a friend here who has done a bit of impromptu dinghy tugboating. Definitely something to keep in mind this can and does happen

 

[Sizzla]

anything above 45 hp I would go 4 stroke. Below 45 hp if it were me 2 stroke
2 stroke pros:
More torque
Easier to fix-probably easier to find parts in less developed places
At one point in time more reliable than low hp 4 strokes (this may no longer be the case)
Lighter
Workhorse

Cons
Gotta mix your fuel
Dirty, louder, smoky

This is for outboards under 45 hp. Once you get above that a four stroke makes much more sense.

 

[Gunny]

Don’t discount the subject of noise as that can be a huge difference in quality of life on board when running an outboard

 

[noexit]

I see a lot of comments on the noise and smoothness of a 2-stroke vs a 4-stroke, saying 4-strokes are smoother. This really depends on the size and number of cylinders. I have two 8hp 2-stroke twins and one 6hp 4-stroke single. The 2-stroke twins are much smoother and quieter than the 4-stroke single. Water cooled are quieter than air cooled as well.

Size and weight could be an issue too. For me, compact and light weight are very important since my engine well is limited in space. My 2-stroke 8hp Suzuki and 4-stroke 6hp Evinrude won't don't fit properly in my engine well. The Suzuki is oil injected, which means no pre-mix and much less pollution. My 2-stroke Yamaha 8hp is much more compact and quite a bit lighter than the other two. Size might not matter on a dinghy, be weight probably does.

This is all experience in the "mother ship". If I didn't have size or weight constraints, I'd go with the smallest 2-cylinder 4-stroke I could get. 4-stoke engines last longer, pollute less and have better fuel efficiency. Electric would also be a good option. I've messed around with my friend's torqueedo, and it's an awesome motor. It is SO quiet. Expensive though.

 

[Capt Bligh]

For the purist, obviously thev4 stroke. For the pragmatic cruiser, the 2 stroke. "A few extra pounds" is a bad trade off. Most of us have no trouble hoisting a 50 lb motor ont a deck, onto the back of a dinghy, or dragging a dinghy 100 feet back to the water because we misjudged the tide! Those "few extra pounds" make them all a Herculean tasks. The Tohatsu 9.8 ( if you can still find one) weighs in at 56 pounds, and can easily get two adults, a dog and child up on a plane in a 10 foot RIB. Here in the PNW we often leave the mothership in a nice protected anchoage and explore the shoreline for miles for miles around being able to get up on a plane, in my mind, is #1 priority. Having to muscle around a 100 lb motor is not fun.

 

[Peter Cullum]

When we headed to the Caribbean a few years ago we bought a 15hp Yamaha 2 stroke engine from a bloke who had just come up from there because they are ubiquitous in that area and everyone has parts and the knowledge to fix them if necessary. Never actually had a problem with it, however.

 

[don54321]

I own the same 8 hp, 2-stroke Tohatsu, circa 1994. Best engine I ever owned. When I finally had some problems about 5 years back, I ordered a new OEM carb with its built in fuel pump for ~$190. Took me about a half hour to replace / adjust. All problems solved. As to not lose a precious summer sailing weekend or 2 waiting for delivery, (especially since there was no guarantee the carb was the fix) I bought a late model 4 hp Yamaha 4-stroke off craigslist, as it was available used, that day, decent price, and would work to get me in and out of the slip, which it does surprisingly well. It worked really well, perhaps since it shares the same block as the Yamaha 6 hp, but is throttle limited. Comparing the 2 outboards, the weight is almost exactly the same, 60 lbs. The Tohatsu 8 hp is twin cylinder, so smoother. The Tohatsu is roughly as quiet at similar power output, meaning with the throttle backed down to match the 4 hp motor in thrust. Both motors are much noisier from 75% throttle up, so I usually motor rather slowly as I am usually tending to sails, etc, and I need the time anyway. I use about 3 Gallons of gas per season on the 8 hp. At the same weight, I'll take twice the power. The 2-stroke does not visibly smoke, and I don't believe that emmissions is significant given the low usage. If 2-Strokes were available new in the US, I would would be a Tohatsu 2-Stroke loyalist. My only knock against the 4 strokes is added maintenance of oil changes and greater weight.

 

[BGeff]

"Nice Pair" had 2 8hp Johnsons 2 stroke and they ran and ran and ran...non stop for hours on end at times during long deliveries, with no worries. Filled up the gas tanks on the go with 6 gallon jury cans into each 18 gallon tank. At times, we pre mixed, other times, mixed while underway. Never had issues once everything was all dialed in.

I understand the pollution concern and that has to be resolved with one's own conscience.

 

[KBNJ]

Do you think anyone has ever put a good 2-stroke engine in a dumpster? They get sold on to other people who use them instead of you.

For the record, I pretty much did just that. Granted, it was 30 years old at the time, but it started faster than my new Honda, ran great and wasn't ridiculously picky about fuel. I put the boat in the water that year, watched a sheen of oil slowly encircle the outboard, and then my conscience started screaming at me. I thought for a half a second about selling it and realized how hypocritical that would be. So I tore it apart and sold the metal for scrap. I won't, and really can't, get judgy about what others do (I'm very far from perfect). I just wanted to point out that some dirty old 2-stroke engines DO get permanently taken out of the water we enjoy by people whose consciences are sometimes more compelling than a few bucks.

 

[lom]

For the purist, obviously thev4 stroke. For the pragmatic cruiser, the 2 stroke. "A few extra pounds" is a bad trade off. Most of us have no trouble hoisting a 50 lb motor ont a deck, onto the back of a dinghy, or dragging a dinghy 100 feet back to the water because we misjudged the tide! Those "few extra pounds" make them all a Herculean tasks. The Tohatsu 9.8 ( if you can still find one) weighs in at 56 pounds, and can easily get two adults, a dog and child up on a plane in a 10 foot RIB. Here in the PNW we often leave the mothership in a nice protected anchoage and explore the shoreline for miles for miles around being able to get up on a plane, in my mind, is #1 priority. Having to muscle around a 100 lb motor is not fun.

This is awesome thanks for the info! The practical application of less weight for the power seems to really make sense. The idea of being able to leave the mothership and use the dink for adventure is awesome and is sorta the reason we aren't going electric or a 3hp 4 stroke.

I own the same 8 hp, 2-stroke Tohatsu, circa 1994. Best engine I ever owned. When I finally had some problems about 5 years back, I ordered a new OEM carb with its built in fuel pump for ~$190. Took me about a half hour to replace / adjust. All problems solved. As to not lose a precious summer sailing weekend or 2 waiting for delivery, (especially since there was no guarantee the carb was the fix) I bought a late model 4 hp Yamaha 4-stroke off craigslist, as it was available used, that day, decent price, and would work to get me in and out of the slip, which it does surprisingly well. It worked really well, perhaps since it shares the same block as the Yamaha 6 hp, but is throttle limited. Comparing the 2 outboards, the weight is almost exactly the same, 60 lbs. The Tohatsu 8 hp is twin cylinder, so smoother. The Tohatsu is roughly as quiet at similar power output, meaning with the throttle backed down to match the 4 hp motor in thrust. Both motors are much noisier from 75% throttle up, so I usually motor rather slowly as I am usually tending to sails, etc, and I need the time anyway. I use about 3 Gallons of gas per season on the 8 hp. At the same weight, I'll take twice the power. The 2-stroke does not visibly smoke, and I don't believe that emmissions is significant given the low usage. If 2-Strokes were available new in the US, I would would be a Tohatsu 2-Stroke loyalist. My only knock against the 4 strokes is added maintenance of oil changes and greater weight.

There is someone we've shared an anchorage with a few times who has one of those. Runs like a top and seems smooth and not loud. He's got an apex RIB and with just him and some supplies he flies. The comparison with the lower hp 4 stroke yam is good to know!

 

[sailflat]

Just get one of these...