2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

[kfa4303]

2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

All things being equal, which is better a 2 or 3 cylinder version of an outboard of same make and hp rating? For example, it seems as though 3 cylinder versions of 30-40hp motors are much more sought after in my area than the same version of the motor with only 2 cylinders.

 

[Chris1956]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

3 cylinder, 2 cycle motors usually run smoother than 2 cylinder, 2 cycle motors. Of course, they may weigh more. What are your criteria for "better"

 

[Frank Acampora]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

A three cylinder engine of the same displacement will generally develop more torque at partial throttle and/or lower RPM. This will generally translate into a faster hole shot. In marginal applications it may mean the difference between getting on plane and not plane at all.

Generally, the less number of cylinders, the less internal resistance and the MORE horsepower developed per cubic inch---but, you are asking about two equal horsepower engines so this doesn't apply. Additionally, there is a limit on cylinder size because of total engine aesthetics so the easiest way to more cubic inches is adding cylinders. (Physically, there is no limit on cylinder size: larger steam engines and big diesels can have pistons over 2 feet in diameter)

So: Which is better? As written above, you need to define what "better" is.

 

[pootnic]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Other than the hp, I doubt much is going to be equal.

 

[kfa4303]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Thanks y'all. That's sorta what I thought. It seems like it's more a difference of how the power is delivered than total power delivered. It seems like a 3 cylinder motors generally let you get on plane a bit more easily and run smoother/quieter overall, which would contribute to "better" mileage, hole shot, cruising speed, etc... I only ask because the 3-cylinder versions of a given hp motor seem to sell more quickly down here in FL despite having more moving parts and generally weighing more.

 

[Red9654]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

the 3 cylinder is going to run a little better because it operates on a 120 degree crankshaft compared to a 180 or 360 degree in a 2 cylinder making the 3 cylinder smoother

 

[jimmbo]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

It is far easier to tune the exhaust over a wider rpm range on a 3 cylinder than a 2. It might result is slightly better fuel economy and a better torque curve.
With more cylinders making the power the engine is smoother but less peak strain is placed on the drivetrain allowing the use of smaller gears and housings

 

[Home Cookin']

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

from a guy with old motors that don't always run right: a three cylinder with one cylinder not working will get you home just fine!

 

[Home Cookin']

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

here's a question: would one get better fuel efficiency ("gas mileage") than the other? Enough to matter?

 

[kfa4303]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

yeah, I would think any differences would be pretty slim, but guys go nuts over the 3-cylinder versions of Yamaha and OMC motors down here in FL for some reason. I guess they're just splitting hairs, or trying to be a little smoother/quieter ride when sneaking up on fish, or something. Sorta like a V8 vs. V12 engine. They're both powerful, just in different ways. Grunt vs. Grace, Mustang vs. Jaguar. That sorta thing.

 

[Frank Acampora]

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

Re: 2 cylinder vs. 3 cylinder outboard of the same horse power. which is "better" ?

It takes X amount of fuel in a similarly designed engine ( ie. crossflow or loop charged), to generate Y amount of horsepower. It doesn't matter how many cylinders do it. Crossflow engines are generally more thirsty than loop charged.