is there a major difference in performance between a 2 cyl. and a 4 cyl.?

[psinatra]

I'm looking at buying a mid 80's 2 cyl. 60. johnson. Now I grew up with a 4 cyl. merc. 50.


I'm assuming that the major differences will be smoothness. Is a 2 cyl. more likely to overheat?

 

[Silvertip]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Please think about what you just asked regarding overheating? That simply is a non-issue. What would make you think a two cylinder engine would overheat and a four cylinder wouldn't? They are both water cooled and thermostatically controlled. The number of cylinders has no bearing whatsoever on this. Does a V6 or 4 cylinder car overheat any more frequently than a V8? How about your lawn mower -- it has only one cylinder.

 

[psinatra]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Please think about what you just asked regarding overheating? That simply is a non-issue. What would make you think a two cylinder engine would overheat and a four cylinder wouldn't? They are both water cooled and thermostatically controlled. The number of cylinders has no bearing whatsoever on this. Does a V6 or 4 cylinder car overheat any more frequently than a V8? How about your lawn mower -- it has only one cylinder.

so..I take it that's a no....


When talking about a car, rarely does a v6 have the same horsepower as a 4 banger. 4 cylinder cars are often around two litre marks and V6's are often around 3.0 or so.


but many 50's are 2 cylinders and many of them are 4. I'm asking about the pros/cons of each.

 

[Lion hunter]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

On the car subject you are correct many 4cyl have less power than V-6's.....Because they are smaller displacement. When comparing a 50hp motor both are making 50hp regardless of the number of cylinders.

As far as reliabilty goes the thing that would concern me most is the length of production. Was the design in production for a long time or was it a one year wonder.

 

[kencat]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

How about what is the difference between a 2 cyl 60hp and a 3 cyl 60hp made by the same company - OMC. What purpose did that serve? There must have been different intended markets for each...I can only guess that the 2 cyl is more utilitarian and perhaps more sedate with broader powerband vs the 3 cyl being more of screamer.But then 60 hp should be 60 hp....unless some fudging of numbers was going on

 

[Lion hunter]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Just like everything outboards evolve through time. Different engineers, use less material, cheaper production, emissions who really knows the entire story of why they would change design. My initial guess on the v-4's vs 2 and 3 cylinders is size. My old 60hp is huge. Then you look at newer models and wonder how they got 60hp under that little hood. Changing markets make people want different looks and companies have to change to sell product. Marketing people are constantly trying to 2nd guess what people want and if another company is going to produce a sleeker looking motor they try to do everything they can to hold their market share. Even if it's abandoning a proven design. There are probably many other reasons but I'm sure I'll never know them.

 

[Chinewalker]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Actually, the 60hp Johnrudes of 2 and 3 cylinder varieties never existed side by side in a given year. In the mid 1980s, when motors began to be rated at the propeller, as opposed to the powerhead, the 60hp twin became a 50, while the 70hp triple became a 60. The 75hp triple became the new 70...

 

[Silvertip]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

The number of cylinders an engine has has no bearing on how much horsepower an engine can make. Horsepower per cylinder is what makes a multicylinder engines total horsepower. But one could design a 100 HP one cylinder engine just as easily as one could design and 100 HP 10 cylinder engine. Neither would be desireable because of the roughness (one cylinder) or the complexity (10 cylinder). So engine design is all about compromise. In the case of two cylinder Johnson/Evinrudes, they concentrated on two cylinder designs in the the smaller motors for decades and the reliability has been superb. Yes, there have been crossover years where two and three cylinder versions with the same HP existed but that's only because a mid range designs went to three cylinders. Higher HP versions went to V4, V6, and even V8 designs. Years ago Merc for example went with an inline six in their high HP versions which was a skinny motor but stuck up on the back of the boat like a tree stump.

Since your original question was about "the major differences" here they are. A two cylinder Johnny/Rude is a 747cc engine. A three cylinder Merc is 967cc. The J/E has a 2.42:1 gearcase and can swing 12 - 13 inch props. The Merc (non-big foot) has a 1.83:1 gearcase and swings a 10 inch prop. The Merc will be a tad faster once on plane. The J/E will get the same boat on plane quicker. How do I know this? Been there with both engines. Fuel consumption is a wash. 50 HP = 5 gallons per hour at wide open throttle give or take a tad and that ratio (10% of rated HP) is true for any marine engine.
For ease of service, simplicity, parts availability and overall reliability my choice is J/E. If high end performance and a little more smoothness is your only measure, go with the three cylinder Merc.

 

[sho3boater]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Most motors I see a difference in is when they detune a larger motor. For example the V4 85hp Johnson in the 70s. Friend of mine got one and put it on like a 20' deck boat, big heavy trihull under it. That thing with no power trim will pop on plane in no time. It is not that fast but the speedo was showing 35mph in that tank. In comparison my current 85 Force is a three cylinder and on a smaller boat (16' vee), sure it does over 40gps but I'd say it does not get on plane any faster. It has way less torque but I'd guess the same peak hp of 85hp. So those detuned motors sure are the ticket for heavy hulls, the smaller one may work better on a light hull. I also had a 80hp Merc I4 that might have been tired, it seemed to get on plane slower yet but went ok at max rpm on another 16' vee.

 

[freetime99]

Re: is there a major difference in performance between a 2 cyl. and a 4 cyl.?

Ive owned 2 cyl and 3 cyl johnnyrudes , 8 all told, and the 3 cyl engines were all a lot smoother running than the 2 cyl.( in the 50 to 70 hp range ) Ive been around a number of 4cyl johnnyrudes, and they had no advantage over the 3 cyl other than the horsepower produced - this is 45 yrs experience with these engines.