Fuel cut off inertia bypassed, how many guys have not noticed this

[Moraystag]

Having fitted refurbed carbs, I had a sticking needle valve which led to overflow and dump of fuel.
Had been advised that stopping the power to the pump using the fuel cut off manually will obviously stop the flow of fuel to the carbs, and with the car running will empty the float bowls on the carbs.
Went to check that the fuel cut off was working and low and behold it had been bypassed electrically. I had never taken much notice of it previously and deffo had never taken the time to make sure it was wired up and operational.
Luckily I contacted local SOC member ( Alan, Inverurie ) who explained how to get into this, clean it, and connect it back up. Luckily, although corroded inside it was not beyond repair, and after strip down and clean up it seems to be working as it should.
This now got me thinking , just how many other Stags have these bypassed/disconnected, and taking into consideration the fuel cut off is a safety device to avoid a fire if involved in an accident, it may be worth letting others know so they can check their own ones.
Not sure, but assume that this may have been covered before, anyway there will be newer members who are unaware of this particular component, and what it should do, if they had a shunt.
Only posted this in the interests of safety, as it was obviously originally fitted for a reason.
Have attached pics if at all interested.
PICT0125.jpgPICT0124.jpgPICT0123.jpg
Mike

[ChasR]

Out of the many things bypassed on my car the inertia switch wiring was original and intact! .

[DJT]

Good point Mike. I would keep the by-pass link in the boot, just in case you get a problem in future and want to link out the cut-off during fault finding.

FYI the ball bearing doesn't complete any circuit. The circuit goes through the brass springs and through the collar on the plunger. In the event of an accident, the sudden stop causes the ball to jump up and knock the plunger up, thus breaking the circuit. This is the 'inertia' that gives the switch its name.

If you want to manually activate the switch, just pull the plunger up. Pushing it down re-sets it. In fact doing this regularly helps keep the contacts clean.

Dave

[KOY 23]

Good point Mike. I would keep the by-pass link in the boot, just in case you get a problem in future and want to link out the cut-off during fault finding.

FYI the ball bearing doesn't complete any circuit. The circuit goes through the brass springs and through the collar on the plunger. In the event of an accident, the sudden stop causes the ball to jump up and knock the plunger up, thus breaking the circuit. This is the 'inertia' that gives the switch its name.

Dave

Dave.

I have never bothered to think why the inertia switch was so called, your description describes it perfectly.

Thanks..

John.

[dasadrew]

Good points. Engine bay looks smart! For any new readers, a reference pic:

IMG_3010 (Custom).JPG

[Moraystag]

Drew your photo makes it even clearer for others, I forgot to take pics when I stripped the inertia switch down. Your ball bearing looks to be in way better condition than mine though.
Sorry for some what poor & slightly incorrect description, but I think I have managed to get my point across, and will probably cause a flurry of activity as far as this device is concerned. However I hope this post may prompt others to check it out, as I certainly had never really took much notice of this before as it seemed to work.

Mike

[staggering]

Mike - a very important safety issue raised in you're post + I wonder what view an insurance company would take if a serious road accident / fire incident occured which results in a police investigation / technical strip down of the car only to find a safety system to be by by passed in this way.

Regards
Ian

[Guest]

When I bought my Stag, the seller showed me the cut out sitting in a cardboard box in the boot with the other spare bits and pieces. I never asked him why it was not fitted because I never knew they had them and then forgot about it. I have never seen another car (non injection) with an electric pump and a cut out, so what is so special about the Stag design? I wonder why the PO took it out?

[dasadrew]

... so what is so special about the Stag design?

Perhaps someone at BL got it into their heads that cars in America always end up on their roof in an accident, hence the T-Bar and a fuel cut-off which works when the car is upturned! Maybe he watched too many American films?

[peterrc]

Good point Drew. Would the inertia switch work in a front end smash or is it only designed to operate on 'roll overs'?
Peter, cupar

[Moraystag]

After I overhauled this yesterday I notice that if you tap it when it's sitting vertical, it will cut off.

[StagnJag]

How hard did you tap it? you don't want it to activate every time you go over a pothole!

[Moraystag]

Hard enough obviously!!!!!!!!!!!!!!!!!

[Moraystag]

When I bought my Stag, the seller showed me the cut out sitting in a cardboard box in the boot with the other spare bits and pieces. I never asked him why it was not fitted because I never knew they had them and then forgot about it. I have never seen another car (non injection) with an electric pump and a cut out, so what is so special about the Stag design? I wonder why the PO took it out?

Don probably the same reason the previous PO of mine removed it. Because it was not working or working when it should'nt have been

[Danny]

Hi Mike,

Tested mine last year without really realising it. I had the unit off the bulkhead for cleaning the area, it activated (or it might be de-activated) it's self when it was hanging down. Later in the evening when I went to put the car away I could not understand why the car would nor start, too me a while to remember that I had moved the cut out during the day.

All good fun.

Cheers
Danny