Someone told me that at one time Mercury's 115hp engine had a "2-4" operation where at low rpm the motor ran on two cylindars and at high rpm it ran on all 4. Is this true? When did they produce this? Is it still used? Was it any good?
its called a 2+2. at low speeds, it would only run on 2 cylinders, for whatever reason, save gas, lower emisions, whatever. those crazy mercury engineers, i tell ya, they are wacky!
It was to smooth-out the idle. When it banged on all four it shook someting awful. They still make them, or this is the first year they don't. Started in the late 80s. Except for that one quirk, they're decent motors.
I have one on a Myacht. At idle speed it is a bit of a thudder. I think it starts hitting on all four at app 2000 rpm. It's actually throttle position dependent. The lower 2 carbs are just missing most of their idle circuitry. Pretty stupid IMHO. If cutting off 2 cyls makes it idle smoother then the wrong firing order was chosen when the engine was designed . I bet they didn't start from a clean sheet of paper saying they were going to have it idle on only 2 cyls. It is a bandaid they were forced to adopt to mask the design flaw.
I've got a 100 2+2, it ain't all that bad, you get 'used' to it. <br /><br />Actually not all that bad since there's a speed restriction of 4 knots where I launch my boat, once out of the channel and I'm off.
