Running wires up the handle is a false economy.
There a hole in the carb, if it is not blocked its a source for dirt to get in the mower.
The pin rubber goes in the hole, its the perfect fit to block the hole. The pin goes down the centre, this sees that the rubber cannot be disslodged.
Theres a 'cam' on the grey rotator valve in the carb that bumps the pin across to make the contact with the cross pin.
Fuels and oils can effect the rubber on the pin and make it soft and split etc. So sometimes it needs to be replaced.
Chances are if it was working perfect before, with a new rubber it will be good to go again.
The pin rubbers are usually $1-1.50 at a mower shop.
A lot easier to replace with the carb off. If you are taking the carb off i would suggest renewing both the o-rings on the linlet manifold as well. As well as removing the primer face on the carb and cleaning the carb 'bowl' out. Put a new O-ring on the primer face as well, take care not to loose the needle. 4 parts, the face, the needle the float and the o-ring.
In the case of your suspected seized mower; If it is good to go again, i would suggest getting an o-ring for under the starter while you are there. All up it should be about $10.
