Variable ratio throttle linkage

A variable ratio linkage for a throttle valve having a rotary shaft, the linkage comprising:

• a primary lever having a fixed end for attachment to a throttle shaft, a free-end radially spaced therefrom, and a central region;
• a secondary lever having first and second ends, a pivot therebetween, a slot located between the second end and the pivot, and a roller moveable within the slot and selectively securable to the secondary lever, the secondary lever being attached to the primary lever and rotatable about a pivot axis generally parallel to the throttle shaft, the secondary lever first end cooperating with the primary level to provide first and second limits for restricting the relative rotation therebetween, the secondary lever second end adapted to abut a stop for limiting the movement thereof;
• and
• spring means for elastically biasing the throttle shaft to a closed position where the secondary lever first end engages the first limit and the roller abuts the stop, wherein movement of the secondary lever first end away from the first limit causes the primary and secondary levers to rotate relative to one another and slowly rotate the throttle shaft until the secondary lever first end engages the second limit, whereupon further movement of the secondary lever first end away from the first limit causes the throttle shaft to rotate at a relatively faster rate.