2 stroke vs 4 stroke outboard

[lestersails]

Assuming you have a salt water use for this, do not buy Suzuki. Kind of infamous for salt water corrosion of cooling passageways inside the engine, which is difficult or impossible to fix. Don't know if it is true still, but my manual (which I think was 2015) said that if you use it in salt water it is required to do a fresh water flush after every salt water run. PITA for a Chesapeake boat. Darn near impossible for a cruiser, I would imagine. Warranty written to not cover this problem.

[KPowell]

Power to weight is better with 2 stroke since they have fewer parts but they use fuel faster. On a small boat the lower weight of a 2 stroke might be better. I am using a 4 stroke because that's what they sell in Oregon/Washington. When I am done with my motor at the end of the day I unplug the fuel into the engine and let the motor run until it stops so there is no fuel inside the engine to sit and cause issues inside the carburetor. Things come up and it may be weeks before I can use the motor again. It's a good idea to do motor oil and lower end oil changes on a schedule. I always lift/tilt my engine out of the water at the end of the day. I am a day sailor a couple times a week in the season so I change my oil every spring even if it looks okay. If it's in salt water change the zincs when needed. An engine in my situation should last at least 30 years if taken care of. I have a newer outboard, I am in my 60's, this motor should live longer than me.

[sv Stella Maris]

Let use criteria decide:

For lite-weight and nearly maintenance free: 2 stroke all day

For quieter and more fuel efficient: 4 stoke

Where we cruise in the Caribbean, mechanics are not available, so 2 stroke is the only dependable option for those that rely on it for transportation.

Also, allows us a smaller dinghy, to pull her up on the beach, and stow her in the davits with ease versus the 4 stroke EFI beast we gave away…but it was quiet ;-)

[rslifkin]

Originally Posted by sv Stella Maris

Where we cruise in the Caribbean, mechanics are not available, so 2 stroke is the only dependable option for those that rely on it for transportation.

That one depends on one's mechanical abilities, I think. Depending on where we are and what fails, I might need to get parts shipped in, but short of damage bad enough to require a machine shop, I doubt there's much I couldn't fix on any small outboard (other than maybe failed EFI without the tools to diagnose it). Even a small 4 stroke is a fairly simple piece of equipment compared to what pushes most of our bigger boats around.

[sv Stella Maris]

[QUOTE=rslifkin;3864397]That one depends on one's mechanical abilities, I think.”


Meh…I used to overhaul & maintain small engines when racing motor cross, have taken for certification engine overhaul courses for modern EFI & VVT four-stroke engines, perform 80% of our family’s mechanical needs aboard (we are 10 people on a 60’ cat)…

The big difference is: I don’t maintain NOR am given access to the necessary Yamaha software to service these modern outboards…BUT moreso: my Yamaha two-strokes flat-out have NEVER broken.

My 9 year old can pull-start our 700cc 40hp Yamaha, and my 5 year old can pull the 15hp Yamaha…both Enduro models.

Even when I assist with salvage and suck pure mud or sand into the intake, my Enduros survive without maintenance. That would never happen with my previous hi-tech 4-stroke engines…

[wsmurdoch]

The new Tohatsu 4 stroke EFI 8 and 10 hp outboards [MFS8/9.8C(W)] weight 38.5 kg (84.9 lb). The old Tohatsu 2 stroke carbureted 8 and 10 hp outboards [8B/9.8B] weigh 26 kg (57.2 lb). That is a 12.5 kg (27.6 lb) difference. To me the 4 stroke is significantly heavier than the 2 stroke. It is a significant weight on the transom of the dinghy, and a significant weight as I lift or carry the motor.

[MVDarlin]

My 25 hp 4 stroke Honda lasted 25 years in salt water with one head gasket replacement. I recently replaced it in MX with a 15 hp Yamaha. I start each season with a fresh tank of gas and it runs great. Recomnend 4 stroke.

[rapanui 2]

[QUOTE=Networker;3861816]If you were going to buy a new outboard, say a Yamaha 9.8 2 stroke vs 4 stroke, which would you go for and why?

I have a 4 stroke that has less than 50 hours and always does. I like it when it works, but it’s rare.

Getting a new one now in Caribbean and keen to get another 4 stroke, but perhaps I’m best off with a 2 stroke? Do they go the same speed and use the same amount of gas?

Keen to learn practical pros and cons of each.


my experience is 2 stroke easy to repair lighter and more nervous the best brand from far is yamaha but the problem with yamahas 2 stroke is they are often stolen because they have high resale value and easy parts to get , so its better to have less appealing motor as mercury, tohatsu, selva ....

[Tupaia]

[QUOTE=rapanui 2;3864704]

Originally Posted by Networker

If you were going to buy a new outboard, say a Yamaha 9.8 2 stroke vs 4 stroke, which would you go for and why?

I have a 4 stroke that has less than 50 hours and always does. I like it when it works, but it’s rare.

Getting a new one now in Caribbean and keen to get another 4 stroke, but perhaps I’m best off with a 2 stroke? Do they go the same speed and use the same amount of gas?

Keen to learn practical pros and cons of each.


my experience is 2 stroke easy to repair lighter and more nervous the best brand from far is yamaha but the problem with yamahas 2 stroke is they are often stolen because they have high resale value and easy parts to get , so its better to have less appealing motor as mercury, tohatsu, selva ....

Tohatsu M9.8B would be my choice. Almost 10kg lighter.

[rslifkin]

Originally Posted by wsmurdoch

The new Tohatsu 4 stroke EFI 8 and 10 hp outboards [MFS8/9.8C(W)] weight 38.5 kg (84.9 lb). The old Tohatsu 2 stroke carbureted 8 and 10 hp outboards [8B/9.8B] weigh 26 kg (57.2 lb). That is a 12.5 kg (27.6 lb) difference. To me the 4 stroke is significantly heavier than the 2 stroke. It is a significant weight on the transom of the dinghy, and a significant weight as I lift or carry the motor.

In the sense of lifting the outboard on and off the dinghy, yes, the 2 stroke is lighter. But it's not necessarily much lighter in terms of the overall package. If the 2 stroke burns enough extra fuel that you end up wanting a 6 gallon tank instead of 3 gallons, you've just added about 20 lbs for the larger fuel tank and extra fuel, eating up most of the weight savings from the lighter outboard.

[malbert73]

In the 15hp range the Tohatsu 15 4 stroke EFI is only 10-12 lbs more than a Yamaha 15 enduro.

I would never go back. Having recently chartered a boat with a 15 hp 2 stroke, the smell and rougher slow speed were jarring after 5 years with the 4 stroke EFI. Additionally, slow speed harbor cruising which is a lot of destinations- and the Tohatsu is super smooth

[wsmurdoch]

Originally Posted by rslifkin

In the sense of lifting the outboard on and off the dinghy, yes, the 2 stroke is lighter. But it's not necessarily much lighter in terms of the overall package. If the 2 stroke burns enough extra fuel that you end up wanting a 6 gallon tank instead of 3 gallons, you've just added about 20 lbs for the larger fuel tank and extra fuel, eating up most of the weight savings from the lighter outboard.

A Tohatsu 8 hp 2 stroke uses 1.1 gal/hr at full throttle. A Tohatsu 8 hp 4 stroke uses 0.85 gal/hr at full throttle.

With a 3 gal tank the 2 stroke will run 2.7 hr at full throttle. To lighten the load with the 4 stroke, you could put 2.3 gal of gas in the tank and run full throttle for the same 2.7 hours. The 0.7 gal of gasoline left out of the tank would weigh 1.9 kg (4.2 lb). The dinghy with the 12.5 kg (27.6 lb) lighter 2 stroke motor would still be 10.6 kg (23.4 lb) lighter and thus faster.

https://www.tohatsu.us/index.php?main_page=page&id=19

[donradcliffe]

My daily dinghy driver for 10 years was a tohatsu 3.5 hp 2 stroke. NEVER was flushed with fresh water. Picked it up with 1 hand at 28 lbs. Consumed a jerry jug of fuel every 2 months. When the spark coil starting going out in Northern Australia, I stopped a small town dealer. He had the distributor put one on the overnight truck and I had it the next day. It did eat shear pins, so I made my own out of SS. If I left it unused for more than a month, I would have to drain the carb bowl to get it to start. When it got bashed under a fixed pier in waves at high tide, I sold the still running motor and bought a new one. Never stolen, but I spray painted the cover international orange. Six years later I sold that motor for more than I paid for it.

[CaptainRivet]

Originally Posted by Networker

If you were going to buy a new outboard, say a Yamaha 9.8 2 stroke vs 4 stroke, which would you go for and why?

I have a 4 stroke that has less than 50 hours and always does. I like it when it works, but it’s rare.

Getting a new one now in Caribbean and keen to get another 4 stroke, but perhaps I’m best off with a 2 stroke? Do they go the same speed and use the same amount of gas?

Keen to learn practical pros and cons of each.


Steve

Get the Tohastu 2 Stroke 9.8hp MB9.8, the holy grale of the outboards, it weights only 26kg and planes my highfield ultraleite 340 significantly earlier then the 15HP 4 stroke honda.
Milllions of asian fisherman cannot be wrong.
It always starts mostly 1st pull, sometimes max 2nd. My Honda needed min 3 pulls and was not really the most reliable one...the Tohatsu just gets the job done 100% reliable. Won't hesitate a sec to buy it again.

[ixnax]

Originally Posted by CaptainRivet

Get the Tohastu 2 Stroke 9.8hp MB9.8, the holy grale of the outboards, it weights only 26kg and planes my highfield ultraleite 340 significantly earlier then the 15HP 4 stroke honda.
Milllions of asian fisherman cannot be wrong.
It always starts mostly 1st pull, sometimes max 2nd. My Honda needed min 3 pulls and was not really the most reliable one...the Tohatsu just gets the job done 100% reliable. Won't hesitate a sec to buy it again.

Everyone recommending a Yamaha 15HP two stroke is right. Great motors, loved the one I had. Everyone recommending a Tohatsu EFI is more right. I have a 20HP now and it's a marvel for fuel efficiency, sound, environmental considerations etc. As far as parts go, keep spares for either as they will not be available where you are when you need them.