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Random Quote: The fastest way to make something obsolete is to buy it
Bingo. You hit it on the head. Only you must decide what is most important to you. I prefer the 2stk technology for a number of reasons - simple to work on, cheap to fix, cheap to purchase, not all that thirsty on fuel especially the 115 and lower hp.
I have a 2001 Yamaha 2-stroke 115. It's been stone cold reliable for me. One of the best outboards ever produced IMO. Powerful, reliable, and low maintenence costs. I run mine weekly. I know a pioneer tarpon guide in Galveston that fishes a pair of them on a 25 Whaler for 90 days in a row every summer, the "Nasty Ninety" 90 days in a row booked solid with paying customers. The 115 Yamaha 2 stroker is the only engine he will run.
WOW! I feel I just stepped back in time by about ten years. The 115 4-stroke vs. 115 2-stroke"carb" is huge!!!
Lets look at the advantages on the F115.
1. At least 30% better fuel economy.
2. cleaner for the envronment.
3. much, much quieter.
4. easier, faster starts.
5. oil changes so simple even a caveman can do it.
6. longer plug life.
I could go on but I think I got sucked in to either a joke or some sort of time warp.
Btw, unless your family enjoys the fresh aroma of 2-stroke exhaust smoke the 4-stroke makes breathing a whole lot easier.
The f115, yes agree better fuel economy but I figure I can run 2 stroke on fuel and oil for about 2 - 3yrs on the intial cost saving.
The f115 cleaner, yes true but the 2 stroke is progressive oil injection from 50:1 at full noise to a barely detectable 200:1 at idle.
Quiter, yes give you that one, but i'm a bit of a rev head so like to know its puttin the ponies out.
Easier faster starts... on a correctly setup engine there should be no advantage of either.
Oil changes easy I agree but its a cost along with filter, and we havent mentioned valve clearances either or cam belts. (mates f100 has 20hrs on it and on third belt, keeps shredding them)
If you say plugs last longer, willing to accept that one too, but they are hardly expensive.
Not looking for an arguement, just discussing pros n cons, I'm in a position to buy either, its interesting to hear both sides, but the 2 stroke seems to be very popular, and i can see why.
bmkshort - 7/11/2007 12:03 AMWOW! I feel I just stepped back in time by about ten years. The 115 4-stroke vs. 115 2-stroke"carb" is huge!!!Lets look at the advantages on the F115.1. At least 30% better fuel economy.2. cleaner for the envronment.3. much, much quieter.4. easier, faster starts.5. oil changes so simple even a caveman can do it.6. longer plug life.I could go on but I think I got sucked in to either a joke or some sort of time warp. Btw, unless your family enjoys the fresh aroma of 2-stroke exhaust smoke the 4-stroke makes breathing a whole lot easier.
I agree with all of this, maybe you would like to equip it with a loran too..ha, Seriously, I am surprised though about the 5k price difference, how can that be? Here I think it is less than 2K. If it really is 5K less, get the 2 stroke
The F115 is far and away quieter.... It also being fuel injected started instantly, the 115 2 stroke could be down right stubborn when cold. Both engines were great motors, they were on different boats so a fuel burn comparison can't be made. However, I'm certain the F115 is better on fuel.
Bottom line from my experience.... The4 stroke is A LOT quieter and instant start hot or cold, but doesn't have nearly the balls the 2 stroke has. That F115 felt lethargic, but to be fair it was on a 21' bay boat (in signature) and it would still get 4 fisherman, all gear, baitwells & fuel full up on plane with no problem.
i'll give an opinion from a different perspective (and I won't even tell you which is better). This is from the water skiiers view (and the OP said that he was buying for family watersports and fun).
- The two stroke will be better for git up and go for pulling that slalom skier (although still too small in my opinion - I am a barefooter from the old days when anything less than a 200 hanging off the back was too small)
- The 4 stroker will be FAR less intimidating for the younger ones (or any new skier for that matter) if they are back there just trying to get organized on 2 skis (noise and smell - i know the new 2 strokes are better as far as smell goes, but admit it 2 stroke die hards, its still there).
- the 4 stroke is going to save you a lot more money than you think on gas when doing water sports. you use a LOT more gas when you are towing (especially these huge tubes that available today) than when just out cruising. Also when pulling skiers or boarders, you are constantly starting and stopping, very high fuel usage.
Having owned several outboard barefoot (Mastercraft and Malibu) ski boats, and currently owning a Malibu inboard, I'd say its a tough call. If I were planning to do lots of skiing and barefooting, I'd probably go with a 2 stroke. If I had young kids and thought the majority of the family fun was going to be tubing and 2 ski wallying (sorry), i'd go for the 4 stroke.
Now if you want to do some REAL skiing, get yourself an inboard :-)
__________________ 2003 Century 1800 with Yama F115
2000 Malibu Response LX ski boat (325 HP Indmar)
The f115, yes agree better fuel economy but I figure I can run 2 stroke on fuel and oil for about 2 - 3yrs on the intial cost saving.
The f115 cleaner, yes true but the 2 stroke is progressive oil injection from 50:1 at full noise to a barely detectable 200:1 at idle.
Quiter, yes give you that one, but i'm a bit of a rev head so like to know its puttin the ponies out.
Easier faster starts... on a correctly setup engine there should be no advantage of either.
Oil changes easy I agree but its a cost along with filter, and we havent mentioned valve clearances either or cam belts. (mates f100 has 20hrs on it and on third belt, keeps shredding them)
If you say plugs last longer, willing to accept that one too, but they are hardly expensive.
Not looking for an arguement, just discussing pros n cons, I'm in a position to buy either, its interesting to hear both sides, but the 2 stroke seems to be very popular, and i can see why.
Rgds
Ron
Oil burn is only part of the dirty process. 2-stroke carbed motors put out unburned fuel into the water also. Thats why they don't get the fuel economy like a 2-stroke fuel injected or 4-stroke motor. Every time the piston goes down and draws fuel in and then starts its way back up, some of the fuel escapes out the exhaust port. Thats the biggest culprit of that colorful thin sheen on top the water you see behind the boat.
As far as mates F100. 20hrs.? 3rd. belt? Highly unusual.
Did he let the dealer do the work? If so, He needs to contact Yamaha. If not, the dealer should be able to find out why the belt is not holding up.
Recommended belt repacement is every 200 hrs.
Valve clearance inspection every 500 hrs.
I can only speak for my area of the world, but if you try to sell a boat with a 2-stroke carbed motor vs. a 4-stroke or at least a direct injected 2-stroke on it around here, you will lose more on the resell value than you saved on the initial purchase.
If your stuck on 2-stroke technology then go with either Mercury Optimax or Evinrude E-tec because the carburated outboard is on the way out like the dinosaurs and you will be doing the environment a disservice since there are so many cleaner alternatives.
Ron173 - don't let them talk you out of that 2 stroke. I am a big believer in 4 stroke technology, i think they are great. However, i just bought a 90 2 Stroke Yamaha for my 17' Mako. These new 2 strokes are NOTHING like the older ones. I have 20 hours on mine now. There is no manual choke on my motor, it is all electronically controlled. It starts on the first crank everytime no matter how long it has sat or if it is cold or hot. Mine SIPS oil, half the time i can't believe i didn't use more oil. At idle, yes the 2 stroke is much more noisy however they have come a long way with these things and i can still talk normally while cruising. When i bought my motor i had saved enough to by any 90HP motor on the market. I went with the Yamaha because it is bulletproof, HP to weight ratio, and the fact that there are a million dealers in my area. At first i thought i had made a huge mistake, but every time i use it i am amazed and i know i made the right choice.
Before i get flamed about hating on 4 strokes - i KNOW they are great engines, but IMO for the 90 - 115 size range i don't think the added cost and weight is worth it. If you were talking about 150HP and higher i would say go with the 4 stroke hands down.
My good friend has a Century 1901 bay boat with a Yamaha 115 2S. I've run the boat several times for a couple of hours at a time. It performs well (other than having trouble starting occasionally), but the noise and smell are really really obnoxious (especially when moving at slow speed). I guess I've been spoiled by running 4S (or DFI 2S) on my boats for the last ten years. When we're using his boat my blood pressure drops about 30 pts each time we have the opportunity to shut the damn engine off. But $5000 more for the 4S is probably way too much $ for the for the nicety of being almost silent and no smoke/smell and instantaneous starts. I can't wait for my new Tidewater 21 with F150 to arrive so we can use it rather his Century.
Yamaha 115 v4 2 stroke or f115 4 stroke 
