Printable View
It is an inertia switch, so generally takes some sort of impact. The reason for it is that during an impact it will cut the furl supply to try and ensure no fire or fuel spill. It is possible that a branch impact could trigger. However it appears there may be something wrong with yours as they should be reset easily by pushing down from the top.
if somebody is interested, the inertia(fuel cut-off) switches are generally built like in the scheme below
http://i1085.photobucket.com/albums/...chscheme-2.jpg
When a impact occurs, the ball breaks loose from the magnet, rolls up a conical ramp and strikes the target plate which opens the contacts of the switch, pushing it's top presses the plate back in it's place and the contact closes. Theyr problem is that in time the permannent magnet is loosing it's power and it becomes more sensitive cos the ball will wander around there and then it's trouble... it's not very expensive so a 15 -20 years old one it's better to be replaced especially if it worked once without real reason cos then it might happen again soon as the magnet will not become stronger if you see what i mean... in a crisis situation it must be unplugged and bridged the pins in the plug
This device has a remote switch for reset, not a mechanical device for physical reset.
i wanted to show the internal construction and the principle(which is the same) and didnt have other scheme, EDITED