Johnson/Evinrude 18,20 and 25 hp 22ci motors. Don't they all use basically the same components? So is this "advertised hp" or is there really a seat of the pants difference? (bear with me,I have a lot of questions).
While they appear to be the same, there are many differences. They use different pistons and cylinder heads, and carburetors. There is a difference in performance, but don't expect the 25 to run circles around an 18.
Yes, it's the same block. They do the same thing with auto engines. The chev 350 has/had many different horsepower ratings. One of the main things that changes the hp rating is the 'breathing' of the engine. Drop on a 4 barrel carb and a dual exhaust and the hp goes way up. It was the same with the 22 cid engines. They had different carbs and tuned the exhaust differently. Although I have heard that the 22 cid 25hp never seemed to get the full power out of it, but that was subjective. I have several 18hp 22cid's and they're great engines.
That's true. They did funny things with those pistons and heads. One may have higher compression pistons but lower compression head (only a possible scenario). If you can figure out which is the highest piston and combine it with the highest head, you will get a high compression combo. And hard to crank and need premium gas.
And preminum gas may not save the piston. Hit the right combo and put it on an old Champion Hot Rod and it'll run with or better than a Merc 25SS. Trust me.
Well I was pretty sure that a Johnson 20 and an Evinrude 18 were identical. But it wouldn't make any sense to have two different brands owned by the same company with the same hp.
Actually that's about the only time both Evinrude & Johnson have the same motor with different ratings. In most every other case the motor is rated the same for both brands.
For the sake of argument,since they use the same pistons, you could make a 20 into an 18 and an 18 into a 20 by mixing and matching parts. Hey it's Friday.
