New Yamaha 4 Stroke
 

Just read an article in Boating Magazine about repowering and the problems of putting a heavy 4 stroke on an older boat not designed for them. Very interesting considering I repowered two summers ago and faced that very problem. I eventually went from a Merc Optimax 200 to a Etec 175 and lost about 75 lbs in the process. I'm very pleased with the Etec but was surprised to learn that apparently Yamaha has come out with a new lighter 4 stroke 200 that only weighs 487 lbs. which is just about what my old Opti weighed. So I guess there is hope that more options will follow for others like myself that have to repower and could not consider any 4 strokes due to weight concerns.

glanced at the same article from what the said the removed the iron sleaves and sprayed the holes like the did with the old merc black max 200. very hard walls but if something should score them i think its a new block

Another article in Boating Magazine shows that the 4-strokes cost surprisingly MORE to operate than a DI 2-stroke! http://www.boatingmag.com/engines/ou...MjQ1NDU1MzI5S0 Even with the 2-stroke using expensive full synthetic oil, the relatively small savings in 4-stroke fuel costs isn't nearly enough to offset their higher maintenance costs. And this doesn't even consider the cost of the required valve lash check/adjustment on the 4-strokes at 500 hrs. If they had run the analysis for 600 hrs instead of 300, the operating cost difference would have been even more obvious!

If you do your own crankcase oil and lower unit changes you beat the Etec by a long stretch. Using their figures for parts and labor was a slanted atempt for a interesting claim but has little to no real world proof. If you really want to compare ownership costs you need to look at duty service cycles between the engines. Longevity is what truely pays dividends.

I ain't gittin drug into this 2 stroke / 4 stroke battle and I want to stay fair and balanced on this topic, BUT 1) all the oil used to leak out of the Homelight 55 crank case seals and they would explode on a regular basis and 2) you can beat a "water cooled chain saw" for the HP, weight and internal moving parts component combination. (they lowered the ports on the E-Tec's and they have more mid-range torque than a John Deere.....!)
OK, so I'm glad I didn't get dragged into that old argument.

"OK, so I'm glad I didn't get dragged into that old argument"

Speaking of dragging.....the 200 E-tec, especially the HO model, will drag a 4 cylinder 200hp 4-stroke Yamaha allover the ocean. No comparison, no competition........period. Heck, the 200 HO E-tec blows away even the 225 Yamaha in power.

In 10 years one of the two won't be here to compare to. :D We'll be debating 4 strokes vs. boosted diesel outboards.

I seem to remember folks saying 2-strokes were going away back in 2000 when OMC went bankrupt. Although E-TECs are now No. 3 on new boat sales behind Yamaha and Merc, they're No. 1 in repower sales, so they've made an impressive comeback.

Speaking of bankruptcy, I see that Suzuki has pulled out of the US auto market. I'd sure hope they don't abandon the outboard market, as they're my favorite 4S design, and were my 2nd choice for a motor. Their use of an oil bath chain cam drive and the offset crank/extra gear reduction to compensate for less torque sure makes a lot of sense!

Don't count out 2-strokes yet.

Mercury has been working with a higher compression version of their 3.0L air-injected (read: supercharged) 2-stroke multi-fuel motor (based upon the Optimax) which, when burning a JP8/Syntroleum blend, has significantly lower emissions than any current 4-stroke V6 outboard, and is comparable in emissions burning any of the kerosene-based fuels, except No.2 diesel, where it lags only slightly when burning summer blends of diesel.

I understand their initial target market is the military and LEO, but still, it sounds promising.

While the test motors are burning seven different fuels: Jet A1, JP5, JP8, JP8/Syntroleum blend, No.2 Diesel, 93 octane gasoline, and paraffin oil (kerosene-alkane oil), I am told the eventual fuel selection will be limited to 3 grades, which will absolutely include JP5, but probably NOT include gasoline, (even though it will still run fine on a 50-50 blend of gas and No.2 diesel, or gas and kerosene).

The engineer I know who works for Mercury says the difficulty isn't getting the motor to run on any of these fuels, it's programming the computer fuel management system to get similar power outputs from the same injectors regardless of the fuel being used. For instance, they've only been able to get 160-165 hp out of the No.2 diesel and about 180 out of the paraffin, but the JP8/Syntroleum and gasoline configurations have given them 220-230 hp before running into either emission or detonation issues.

Evinrude also has a multi-fuel V6 in testing, but I have no information on that.

Oh yeah, Mercury has a 2.6L Verado tuned to 400 hp that has passed the 2500 hour mark :-) That's the equivalent of 150,000 miles for a car.

BRP has been selling small 2 cyl. motors to the USN for several years http://www.evinrude.com/en-US/engine...ENGINES/MFE_55

They don't want gasoline on their assault ships, but want to run their outboards on the same JP-5 they use in the Harriers and helicopters!