2 stroke vs. 4 stroke weight and power

[work in progress]

I've been trying to educate myself on the pros and cons of 2 stroke and 4 stroke motors before choosing one for my Carolina Skiff j16. Conventional wisdom seems to be that on a smaller boat go with a 2 stroke because it is lighter, stronger, and cheaper. Max hp rating on the boat is 40, which is what I intend to purchase. Yamaha doesn't make a 2 stroke anymore between 25hp and 50hp, so I looked into the ETEC 40hp. (237lbs., $5000) I just found out Suzuki makes a 4 stroke that only weighs 6 pounds more and is actually cheaper. (243lbs, $4800) There goes lighter and cheaper. As for having more power (holeshot), the dealer says the Suzuki will be close to any 2 stroke because it is fuel injected. I'm inclined to believe he is not feeding me a line because he sells Yamahas also, and point blank told me the Yammie 40hp 4 stroke would not come close to a 2 stroke. I would greatly appreciate some direction before I go spend a ton of money on the WRONG motor for my boat.

[Fletch]

work in progress - 9/28/2007 5:10 PM

As for having more power (holeshot), the dealer says the Suzuki will be close to any 2 stroke because it is fuel injected.

I don't know much about the smaller hp motors but that reeks of salesman bs. All things equal, a 2 stroke will generate more holeshot cause it's firing twice as often. A fuel injected four stroke of equal displacement would be efficient but it still can't overcome the extra power strokes the 2 stroke is making.

That said, the 40 hp Zuke is a 3 cyliner whereas the 40 hp ETEC is a 2 cylinder. Displacement-wise, I think the ETEC is bigger though. So, I don't know how all that works out in the equation. Also the higher hp zukes run a much lower gear ratio in the lower unit which allows them to spin a bigger prop. This definitely helps them out on the low end and at cruise rpms (but at the expense of some top end performance). I don't know if the lower hp zukes do the same thing but that's worth a look.

I've ran a 40 and 50 hp Yam 4S quite a bit and while they are smooth running, quiet and efficient engines, I was underwhelmed with their performance. Surprisingly, the 40hp Yam is lighter than the ETEC by about 50 lbs (if I read correctly) though. I think what hurts it the most performance wise is the gear ratio in its lower unit.

If you go to Evinrude.com and select the 40 hp ETEC and then click the "Competitive Comparison" tab, you can get the specs for most of the competitor's 4 strokes. Saves a lot of time trying to look everything up on multiple sites.

I don't know what advice to give you on this one. I don't know many people that own motors in this HP range. I do know that I rarely see any negative reports about any of them online though. Try to ride on as many boats as you can to get a feel for the power of each motor your considering and try to pick one for which you have good dealer support should you ever need service.

[A Few Dollars]

Tohatsu 40. Lighter - 205 lbs, cheaper - about $4000, and as efficient as the others.

[kerno]

as long as there are both two strokes and four stokes for sale, there will be an unending debate about them. There are two stroke fans and there are four stroke fans.

Two strokes have the advantage of usually being lighter, but not in this case. They will also make more power from the same displacement BUT no one ever said or implied that a 2 stroke 40 and 4 stroke 40 have the same displacement, The four strokes are generally larger in displacement, but you can easily check by reading the literature for the various motors.

With a four stroke, you'll run straight gas, but have to change the oil now and then. With a two stroke, you'll be buying two stroke oil to feed the engine. In the horsepower range you are considering, it really comes down to your preference. The resale on boats with 4 strokes is generally higher than two strokes, because there are more people out there who prefer the 4 strokes. In bigger used boats, with engines of 200 hp or more, the ones with two strokes are almost impossible to sell. The ETEC is a good motor and there are people who love 'em. That's great until resale time, when the market just hates two strokes.

[dtmackey]

The 2 vs 4 will never end and it really depends on what camp your in.

My experience with 2 vs 4 was not positive and that is the reason I rebuilt an my 30 year old Evinrude 9.9 so I did not have the penalty of weight. 72lbs of rebuilt weight compared to 90 - 100lbs of expensive 4 stroke was a simple decision, not to mention I converted the 9.9 to 15hp with some simple changes.

Since the motor is used on an Avon removal of the motor is easy at 72lbs, but 100 can be a challenge, not to mention the bulkiness. With this said, I don't care about maintance, fuel cost or the amount of oil burned - the 2 vs 4 is very simple in my situation. Design a 15hp motor that weighs 72 lbs and I'll consider, but after almost 30 years of use, is the 2 stroke really that bad?





D-

[Jon G]

Dt the oldOMC 9.9's and 15's are my favorite engines of all time, the 15 has tons of power for its size and weight, I miss the two that I used to own. Great engines simple and reliable.