Two stroke versus four stroke outboard motor we have been duped

[Davy_S]

I have an opinion here, we have all been sold,or been forced to buy 4 stroke motors, (I have one of each) Many questions are asked ie, which is best for my needs. The requirements my vary, but one thing is certain, lets say 50hp, a two stroke 50hp should (in theory) do the same top speed as a four stroke. The reality is top speed is the same but, the two stroke will leather the pants of a four stroke in acceleration every time, plus it is a lot lighter.
The only difference is this , a four stroke trolls better for fishing, and uses less fuel, but costs more to maintain.
Small dinghy two stroke, far easier and simpler.
Question, have we all been conned and forced to change, are we that gullable?
Your views.

 

[jfm]

Emissions regs

 

[gunman]

But for larger engines, can the manufacturers not get around the emmission regs by EFI on 2 strokes? I understand it makes it too expensive for your 2.5 - 15 hp range.

 

[moonraker 36]

yep.
if their was a low emission's two stroke oil that gave out the same emission's as a four stroke..

hmmm....

 

[adey]

With a two stoke the oil ends up in the sea but with a four stroke it stays in the sump.

 

[Davy_S]

Yes of course I know it was the emssions that caused it, but no-one seems to give a sod about the BP emissions!
I was led to believe that Tohatsu two stroke passed by using fuel injection, I tried a 60 Tohatsu stroker last year, I was Very impressed by its grunt.

 

[Lakesailor]

There's nothing to stop a manufacturer making a two stroke with a pressure oil lubrication system and a sump.
Commer used to make supercharged 2 stroke diesels for their wagons.

The TS3

 

[moonraker 36]

lister black stone did 2/s diesel's opposed piston's..bloody heavy engine!

 

[moonraker 36]

mazda rx7/rx8 rotry engin's take an oil feed from the engine sump.
they pass emission's?

 

[Kawasaki]

Yes a two stroke can be made to pass emissions
The cost/ developement/ research would for tiddlers would be uneconomical I reckon
Lets say a 5hp engine retails in the UK for , I dunno, just a guess a Grand?

OK , one of the best two strokes (although it aint strictly speaking but is sold as such, that's another thread on it's own!) is the Evinrude 'E' Tech range.
Loads of research and developement gone into these motors
Retail price reflects this but they are impressive.

Bigger outboards will still be made, cos at the value/price the developement costs can be recouped
Well, thats what I think.
Could be wrong
No doubt I will be 'told' in a bit!

 

[VicS]

Surely it only the smaller engines that you are being forced to buy as 4 strokes.

2 strokes still available and EU approved in larger sizes From 25 hp and upwards in the case of the Evinrude E-Tec engines

Wanna 50 hp 2 stroke then there's an E-Tec to fit the bill!

 

[Kawasaki]

Yep, tiss only the small ones

 

[jfm]

Wanna 50 hp 2 stroke then there's an E-Tec to fit the bill!

I'm just about to order a 50hp so have been looking at them (on line) Vic. The Etec 50 offers no weight advantage, which surprised me. It's a 2-stroke 2 cyl motor, yet it's 109kg, and Merc/Yam are about the same (112kg iirc) but offer the smoothness of 4 cylinders and 4 stroke (and efi). So I think I'll get the Merc or Yam (can't decide which, but I'm probably splitting hairs and they are the same basic engine anyway; perhaps I'll get the Merc so I can have a Smartcraft display screen)

 

[1973keith]

I'm a big fan of simple carbureted low power two strokes.
In my opinion they are the ideal portable engine, they wash their crankcases clean while running, good power to weight, no valve gear or belts to worry about, no sump oil to pour all over the boot of the car when it rolls over on the wrong side, and if they stop you stand more than 1/2 a chance you'll get them going again. I've got an old 5HP Mercury single cylinder on my tender and I have no plans to get rid just yet!

The whole emissions thing for recreational boating winds me up a treat, the total amount of fuel the average boat engine uses in 12 months is tiny in the grand scale of things. If you're worried about the used oil of a two stroke going into the water then there are biodegradable oils to use.

Once you get up to about 50HP they are thirsty enough to take the enjoyment out of a long weekend, but this is right in the power bracket of the new direct injection 2 strokes. I believe Evinrude even have a 25HP pull start etec now. As the electrical power requirements are reduced for running the injection system we will see more low powered direct injection engines coming along.

Welcome back I say

 

[1973keith]

I'll take the etec thanks

 

[jfm]

I'll take the etec thanks

I'll take a test that is done under proper conditions and measures what I actually want to get out of the engine, thanks

 

[[2068]]

I'm just about to order a 50hp so have been looking at them (on line) Vic. The Etec 50 offers no weight advantage, which surprised me. It's a 2-stroke 2 cyl motor, yet it's 109kg, and Merc/Yam are about the same (112kg iirc) but offer the smoothness of 4 cylinders and 4 stroke (and efi). So I think I'll get the Merc or Yam (can't decide which, but I'm probably splitting hairs and they are the same basic engine anyway; perhaps I'll get the Merc so I can have a Smartcraft display screen)

Not a weight advantage, perhaps, but 4 strokes without superchargers don't have the same acceleration.

 

[jfm]

Not a weight advantage, perhaps, but 4 strokes without superchargers don't have the same acceleration.

Thanks. Yup, the 2 strokes make more torque lower down the rev range. I think I'm happy to trade that for ultra quiet smooth running, but will reflect on it!

 

[1973keith]

4 bangers are quiet, and they are economic. I'll give them that
I had a 2006 9.9 Mariner on a Quicksilver 380 inflatable that was a lovely thing, very nicely finished and never missed a beat. It would push along at almost 20mph all day and I never managed to use a full 12litre tank.

I did however also buy a Mariner Marathon 25HP (tweaked to 30HP ) two stroke. I had visions of swapping engines to suit whether I was pootling along the river, or bouncing around the coast. In reality once the 30 was on the back i never used the 9.9 again. I probably tripled the fuel consumption, while adding 10mph to the top end, but i more than tripled the grin factor.

So you've hit the nail on the head JFM, it's horses for courses.

Good luck, and let us know what you end up with.

PS

If i had to have a 4 stroke I think I'd have a Honda.... they made the choice to use 4 strokes for outboards before anyone else, so they must have got it right by now

 

[timbartlett]

I'm a big fan of simple carbureted low power two strokes.

Agree.
One of the sad ironies of this is that it is the small engines -- the tender shovers -- in which two-stroke has been all-but legislated out of existence.
But if you consider what you need of a tender shover it is:-
light weight
simple
reliable
portable
able to tolerate "abuse" such as being laid down the wrong way up.

All of these point to traditional two-stroke, not four stroke which (by comparison) are heavy, complicated, temperamental, awkward to carry and leave pools of oil all over the car boot.

What makes it particularly sad is that all the virtues of four stroke (quiet, clean, economical etc..) don't really apply to a 4hp engine that is used (in most cases) for maybe 10-20 hours per year.