2-Stroke vs 4-Stroke Outboards

[mako]

I just completely overhauled my Mercury 200hp 2-stroke on my fishing boat. Carbureted. Dead-nuts simple and 100% solid.

That being said, I would give it away for free for a new 4-stroke if I though the $18k investment was worth it on this particular boat (it's not).

I lined the entire cowling with MLV to cut the sound down by 20db, but it still gives me a headache even at idle speeds. The exhaust pollution makes my wife nauseous, and the wind always seems to be blowing from behind by some crazy coincidence.

When I lived in the Middle East I built a boat and it was still possible to buy new Yamaha 2-strokes, but I didn't.

IMO you just don't go out and buy a new 2-stroke in this day and age.

[dmkkeng]

Originally Posted by Funkydrum

I've searched and not found a good thread on this....


I'm a big fan of the lighter-weight and simplicty of 2-strokes and can find a new Yamaha Enduro in the Bahamas. I'll admit that my preferences have been tainted by both the weight and complexity of EARLIER 4-strokes.


Have the 4-strokes improved enough, OR have US buyers convinced themselves that they are 'good enough' as that is their only choice? All the old-school sailers seem to be clinging to their 2-strokes.



This outboard is for my new OC-Tender 330 which needs limited hp and the 8hp Yamaha Enduro is plenty, and crazy light.


Am I overthinking this ?

I have the same size tender with a Yamaha 8hp 2-stroke, I can get up on plane with 2 people and some gear in the dinghy. I definitely appreciate the lighter weight of the 2-strokes especially when having to lift the motor on and off the dinghy. The 2-stroke motors produce more torque at higher rpm's. I'm not so sure that an equivalent 8hp 4-stroke motor would get my dinghy up on plane as easily or at all. The design of a 2-stroke engine is simple which also means it is simple to fix and possibly more reliable if run and maintained properly.

Having said that mixing oil into the gas is a pain in the ass, the stink coming off the 2-stroke engine is offensive. Yes they add to the pollution problem. When I'm in the market to replace my 2-stroke I will be looking to get a 4-stroke engine, every year they are getting lighter. The one caveat may be that I will need to look at a slightly bigger 4-stroke to get the same performance as my 8hp 2-stroke?

[rslifkin]

Originally Posted by dmkkeng

The 2-stroke motors produce more torque at higher rpm's. I'm not so sure that an equivalent 8hp 4-stroke motor would get my dinghy up on plane as easily or at all.

Depending on the power curve, the 4 stroke may just be more sensitive to prop selection and may suffer more if overpropped.

[Jef & Marin, Netherlands]

Sailing is about loving nature, and being in balance with it.
I don't want to be responsible for easily avoided pollution.
2-strokes blow unburnt oil in the marine environment. You really want to do that? The governments are right to stop this, like they stopped leaded fuel.



So we have a 4-stroke.

We chose a 9.8 4-stroke instead of a 15 2-stroke Yamaha Enduro. Both are around 38 kilos. The 9.8 can plane 2 people at 14 knots. Half the fuel consumption.

[Scaramanga F25]

The Mercury 15 two stroke is 25 pounds lighter than the Mercury
4 stroke.