[HAM] Starter motor of my C3 is getting kind of "tired"

[Magnus Enorson]

>I don't think that it is a bad switch because when I lift the start switch
a
>"iii" sound devinitely comes from the starter motor.

This needn't be a guarantee. The way the thing is wired, a failing or
miswired "run" switch (not the start switch) could, and frequently does,
cause the starter to not get up to speed properly. 

The run switch has two sets of contacts, where one makes as the other
breaks. When the power switch is off, the preamp is off and the circuit
allows full power to go to the start motor. As you hit "start" at this
point, the starter kicks in and starts the generator spinning, but lets it
run slightly too fast. When you throw the power switch on, the preamp fires
up and at the same time power to the starter is reduced, causing the
generator to slow down and "meet up with" the correct running speed that the
run motor is trying to achieve. Now you let go of the "start" switch, and
the run motor takes over.

When run switches go bad (and it is very common that they do) they usually
end up in a state where the start motor never gets full current, and
therefore never manages to get the generator up to speed.

/Magnus