Timing advance, why different for outboards?

[thumbnut]

Most of the outboards I've had connect the timing advance with the throttle and have a large degree of stator rotation. Other non-outboard 2 strokes use centrifical advance not connected to the throttle. Or some other electronic method. My f2.5 doesn't seem to have the range of advance as the older outboards I've owned. I suppose the newer larger ones use other varablies also to set timing. Anybody know anything about this? I've wondered about this for many years.

 

[JB]

Re: Timing advance, why different for outboards?

f2.5 ??? Whazzat?

Most non-outboard 2 strokes are designed to operate within a narrow range of rpm or have transmissions or both.

Only outboards and kart racers need maximum torque over a wide range of rpm, thus the wide range of timing.

 

[thumbnut]

Re: Timing advance, why different for outboards?

f2.5 ??? Whazzat?

Most non-outboard 2 strokes are designed to operate within a narrow range of rpm or have transmissions or both.

Only outboards and kart racers need maximum torque over a wide range of rpm, thus the wide range of timing.

2.5 hp 4stroke yamaha. Real powerhouse8). Anyway, I guess what you are saying is the load increases with rpm on an outboard differently than with other applications of the 2stroke, so spark lead becomes more critical. Got it.