Bristol 411 - Fuel Reserve

[David C]

I sent a unit to Four Ashes many months ago but the chap who wound their springs for them either passed away or ceased trading so they are currently unable to repair. Rather a shame as they had got some new bodies made that were ethanol resistant.
I have now decided to fit a Spiyda low fuel level warning circuit instead of having a switched reserve.. This is a tiny circuit board that can be wired in to the terminal board above the battery quite quickly with just 4 wires. Supply plus and minus, sender and fuel lamp. The trigger level is fully adjustable. It requires the incandescent warning light behind the rev counter to be changed for LED as it only supplies up to 20mA but screw in upgrades are readily available. These Spiyda units are currently showing as out of stock but I believe more are being made.
The down side of having a failed reserve unit is that it will draw air from the shorter tube when about 2 1/2 gallons are left so you will only be able to use about 15 and will be hauling around extra you can't use.
Particularly if the car has had long periods of not being used it is worth removing the reserve unit and inspecting the brass gauze. It can either disintegrate or become completely clogged. If the gauze has disappeared it will be straightforward to block the shorter tube and allow you to use all the fuel in the tank.