Okay, the hint is that I had just gotten
through working with the throttle switch and linkage. Also, when
I pressed on the accelerator, the engine did not rev, indicating
a broken linkage somewhere to the throttle. In this case, the
plastic housing on the throttle linkage was so brittle that I
had previously snapped off the hold-down clamp (Figure 1)
while working on the throttle switch. I thought that I could get
away with just snapping the plastic socket of the link end onto
the metal ball of the throttle without using the plastic hold-down
clamp. Wrong! The cupped end of the link would not stay on the
ball when the throttle was rotated. I ran back home and got some
wire and wired the plastic housing around the ball (Figure
2) so that the linkage would not slip off, and then drove
home. Later, I got a spare throttle linkage (one with a good plastic
hold-down clamp) from the junkyard.
This is a throttle end link with a good
functioning hold-down clamp.
The temporary fix was wire wrapped
around the plastic end link to hold it onto the metal
ball of throttle.