2 stroke vs 4 stroke?
- Thread starter dohboy
- Start date
Seafever
Well-Known Member
On the older two-stroke kickers , the plugs always seemed to need attention after putting for hours all day.
Because of the oil mix. If you had computerized auto-oil the mix would change from 50:1 to 100:1 so it wasn't a bad as mixing 50:1 and then running that allday. But the smaller engoines often didn't have "auto inject"
Four-strokes you don't get that as much....but you could run into what they call "make-oil" on a four stroke that is putting along at low rpm all day......especially if it is a "carbureted" fourstroke. EFI not so much.
If the engine does not get hot enough for some reason , it will "make oil".
Because of the oil mix. If you had computerized auto-oil the mix would change from 50:1 to 100:1 so it wasn't a bad as mixing 50:1 and then running that allday. But the smaller engoines often didn't have "auto inject"
Four-strokes you don't get that as much....but you could run into what they call "make-oil" on a four stroke that is putting along at low rpm all day......especially if it is a "carbureted" fourstroke. EFI not so much.
If the engine does not get hot enough for some reason , it will "make oil".
jeffywestcoast
Well-Known Member
I will have to admit , putting down the channel at 5 knots i have to open the sliders or i would be losing my lunch too, 75 johnson..80's vintage, but my 6 hp evinrude kicker i can run all day long without it fouling, had my boat mech out the other day and he was in disbelief, best 250 bucks i ever spent!, was having an idle issue but found it to be a hole in my sqweeze ball, switch the line out with the fuel line i have for the big motor and things were back to normal. I want to buy a 6-8 yammy four stroke in the future but for now i can troll all day on 15 bucks on the two stroke!
There is a huge difference between older designed larger two strokes and more modern 2 stroke designs like Opti’s. My Opti never smokes at all. In fact it runs cleaner than many 4 strokes who’s valve seals are getting a little tired especially, when starting up. We just had the gear box off to rebuild the water pump and the exhaust was very clean and I suspect as clean or cleaner than most 4 strokes. We do burn very expensive DFI oil in it that has its own added cleaners.
As for fuel economy I think the Opti’s do as well as modern 4 strokes because of their Direct Fuel Injection. That technology is now being used on the latest most fuel efficient cars to squeeze every last kilometer out of a drop of gas.
So what about differences. Well you can barely tell my friends big Yami is running when it is at Idle but no problem knowing when an Opti is running and no mistaking that Opti roar when you open it up. They are also a lot less complicated to rebuild than a 4 stroke because there is no complex valve train and they are considerably lighter than an equal hp 4 stroke. Not that you will notice much of a difference in cost if Merc does the rebuilding.
I am often amazed at the difference in fuel economy when compared with older designed Merc two strokes. One of my fishing partners has an older 17 footer with an old school smoky 2 stroke 100 hp main and a 15 hp 2 stroke Merc kicker. Both these motors burn gas like flushing a toilet when you throttle up.
By comparison my 22 foot much heavier hand laid glass boat with a 225 Opti and a 9.9 Yami 4 stroke kicker, burn about the same amount of gas for a days fishing as does the old 17 footer with its old school Mercs. Sure the Yami blows the old 15 hp two stroke away fuel efficiency wise but the 225 Opti seems to burn very little more gas than the old 100 hp Merc despite have 2 more cylinders, 125 more horse power and pushing a much bigger heavier boat.
As for fuel economy I think the Opti’s do as well as modern 4 strokes because of their Direct Fuel Injection. That technology is now being used on the latest most fuel efficient cars to squeeze every last kilometer out of a drop of gas.
So what about differences. Well you can barely tell my friends big Yami is running when it is at Idle but no problem knowing when an Opti is running and no mistaking that Opti roar when you open it up. They are also a lot less complicated to rebuild than a 4 stroke because there is no complex valve train and they are considerably lighter than an equal hp 4 stroke. Not that you will notice much of a difference in cost if Merc does the rebuilding.
I am often amazed at the difference in fuel economy when compared with older designed Merc two strokes. One of my fishing partners has an older 17 footer with an old school smoky 2 stroke 100 hp main and a 15 hp 2 stroke Merc kicker. Both these motors burn gas like flushing a toilet when you throttle up.
By comparison my 22 foot much heavier hand laid glass boat with a 225 Opti and a 9.9 Yami 4 stroke kicker, burn about the same amount of gas for a days fishing as does the old 17 footer with its old school Mercs. Sure the Yami blows the old 15 hp two stroke away fuel efficiency wise but the 225 Opti seems to burn very little more gas than the old 100 hp Merc despite have 2 more cylinders, 125 more horse power and pushing a much bigger heavier boat.
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finaddict
Well-Known Member
My experience has been a little different than yours, RF. I had a 200 FICHT that would burn 45 lph at a cruise of 24 knots and weighed 538 lbs. when the oil tank, and extra 4 litres of oil were included. My new 250 Yammie weighs 558 lbs. and burns 35 lph at the same cruise.
So 10 less litres per hour (about $14.00) plus no DFI (at 100:1 x 45 lph = .45 litres of DFI oil x 14.00/litre = $6.30), I am about $20 per hour cheaper for the same results. The fuel monitor proved it to me and I am completely sold on 4 strokes.
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Just checked the specs and a 225 Opti weights in at 497lbs although some versions may be a few lbs more. It gets about 45% better fuel economy than older designed 2 strokes and is happy with 87 octane. The local Whale boats can get many thousands of hours out of them and they push them very hard all the time. For some reason they prefer the Opti DFI 2 strokes and it sure is not because they are cheaper to buy. Firing every two piston strokes instead of 4 gives them a great hole shot.
Don’t know much about the FICHT but my impression is that they are no Opti.
I will concede the new big Yami’s 4’s get a bit better mileage but the Opti’s are close and a big improvement over older two strokes.
Letting it go now; I am starting to sound like I am getting the ruler out to measure my dick.
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trendsetter
Active Member
Don't forget 4-strokes need oil too, only they use it by way of oil and filter changes every 60-100 hours. Yes 2-strokes use more oil but when you factor in the cost of oil / filter changes it's not as big a difference as you might think.
The Fichts were good but the new optimax and etecs are much better. Also you went to a 250hp so the engine doesn't need to work as hard to push the boat at the same cruise speed. Yamaha, Evinrude and the Optimax are all great motors and each has it's unique benefits.
A few years ago I had the same decision to make...what motor to put on my 14' tinny? The only reason I would buy the 2 stroke was because of its light weight for loading etc but I preferred the 4 stroke for all the other reasons everyone has listed. I went with a 15hp 4 stroke Honda and to make it easier to move around I bought a Crappy Tire 4 wheel carpeted furniture dolly for $20. The only time I have to lift the motor is for mounting and dismounting from the transom...the rest of the time it stays on the dolly and I move the dolly around with a rope handle so I don't have to bend over...works out well and can even pull it over gravel, lawns etc and bring it nice and close to the transom with no difficulty. I have a small piece of 3/4" plywood that I put under the skeg when I lift the motor up and its just the right height that I only have a further 1" lift to mount the motor...pretty easy.
finaddict
Well-Known Member
Good laugh RF, thanks for that. No doubt the Opti's are much better than the first generation DFI's. Each of the newer models (2's and 4's) are light years ahead of what they were even as little as 6 or 7 years ago.
I would be happy with any of the new E-Tec's, Opti's, Yammies, Hondas or Suzuki's. They all have their advantages. Not too many "lemons" in that package
scott craven
Well-Known Member
Lots of discussion lately, so thought I would revive this one....
After running Evinrude, Johnson and Merc 2 strokes and Honda 4 strokes,
the Honda's win hands down. I can't speak for other brands, but my friends
are very happy with their Yamaha 4-strokes as well.
There is maintenance required for both, but 100 hour oil changes are no more expensive
than 2-stroke oil with every fill up.
The smooth power, smoke free running and fuel economy make the 4 stroke a clear winner
in my opinion.
After running Evinrude, Johnson and Merc 2 strokes and Honda 4 strokes,
the Honda's win hands down. I can't speak for other brands, but my friends
are very happy with their Yamaha 4-strokes as well.
There is maintenance required for both, but 100 hour oil changes are no more expensive
than 2-stroke oil with every fill up.
The smooth power, smoke free running and fuel economy make the 4 stroke a clear winner
in my opinion.
I'll weigh in. $20,000 versus $1,000 for a used running and rebuildable 2 stroke, then another $3000 to rebuild it back to new. That is a $16,000 saving. Victoria and Sooke trips are so short that you would never recover the fuel savings. I don't troll on the main so I never have to smell 2 stroke fumes anyways, only the guys following me out in the morning do. 2 strokes are easy to work on so tune ups costs are minimal, (new plugs and new gear oil each year) I can afford to have a rebuilt spare, which I do. I keep an eye out for blown up engines like mine or guys re-powering and grab what I want cheap for extra parts.
scott craven
Well-Known Member
Lol
medherring
Member
I've owned 2 optimax engines both 225 HP, a new 2007 and new 2012. Both cruise at 22 knots using 9 GPH. Fuel economy is the same as any 4 stroke of the same size I have found. Now if they could only make them a little more quiet.
fish stalker
Active Member
Do you think the popularity of podded boats has boosted the 4 stroke market? They seem to be soo much bigger and heavier. I know my transom could not take a 4stroke main and 4stroke kicker.
Finally got a bigger kicker so wont have to troll on my 2stroke main. If we have to troll with the breeze blowing the smell into the boat.... does not make for a nice time on the water, it actually makes me feel pissed off and mad lol my brain does not like it
Finally got a bigger kicker so wont have to troll on my 2stroke main. If we have to troll with the breeze blowing the smell into the boat.... does not make for a nice time on the water, it actually makes me feel pissed off and mad lol my brain does not like it
scott craven
Well-Known Member
Curiosity made me check some Yamaha specs
the F70 4 stroke weighs in at 257lbs
the 75A 2 stroke weighs in at 248 lbs
Virtually the same weight
the F70 4 stroke weighs in at 257lbs
the 75A 2 stroke weighs in at 248 lbs
Virtually the same weight
trendsetter
Active Member
Yeah there are a few light 4-strokes available out there lately. But, if you compare the F75 and the 75A you will see the difference.
F75 = 369lbs
75A = 248lbs
Yamaha also makes a new F200 that is very light for it's size (487lbs.)
I'll mention it again. They shed the extra weight on the new Yami 4 strokes to get them comparable to the 2 strokes by eliminating the steel cylinder liners and using a hardened finish on the bare aluminum bore. So there is no ability to rebuild these blocks if the bore gets scuffed. They are throw away blocks. Bring out another $20,000.
scott craven
Well-Known Member
Pro,
Do you think that adding 4 cylinder liners would add any significant weight to the motor ?
Just an honest question ?
(It may come into play when there are twin 6 cylinders engines)
Do you think that adding 4 cylinder liners would add any significant weight to the motor ?
Just an honest question ?
(It may come into play when there are twin 6 cylinders engines)
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Scott, they also cut material away from the rods and the pistons, they now don't even look like traditional pistons. They end just below the wrist pin hole....no lower skirt area at all. Maybe 3 inches long total. a mechanic friend of mine says this increases the chance for piston slap as it has more ability to wobble in the cylinder. Can't remember if there were any changes to the crank. But I did see the older rods and pistons along side the new ones. I use the direct comparison between a Nascar qualifying built engine and a race built engine. The qualifying engine is shaved wherever possible and pushed to make as much power with as little weight as possible...it only has to last a few laps and be as quick as possible...where a race built engine is beefier with a sacrifice for outright speed but will hold together for 500 miles.
Jerrod, obviously the new 4 stroke engines are performing well for most people and time will tell if the measures taken to reduce weight will also reduce engine life. I just don't like being in the guinea pig group. For me I'll stay with has worked for me for a long time now. I hate opening the hood of a car or truck, or a cowling on an outboard and looking at the rats nest of hoses, belts, sensors, tubes, etc etc...and not knowing where to start. I won't even change a water pump on any of my vehicles anymore...you have to take half the dam front end of the car and engine apart just to get to it.
