Thread: Draining SU Carbs in a Triumph TR4A

G'day all,

My old man had his 65 TR4A rebuilt. When I say rebuilt I mean it spent 10 years with a rivet counter who dismantled it back to constituent parts and re-built it from the ground up as a brand new car in showroom (not concourse) condition. It is bloody spectacular.

Unfortunately between my son and my dad getting cancer and dying, it's not had a lot of use in the last 5 years (there are 887 miles on the odometer - yes that was rebuilt also).

It has a pair of SU HS6 carbs and when new it ran like a clock. Unfortunately a series of sunday drives saw repeated carbs full of fuel evaporating. So much so the needle on the front carb looks more like rust than needle (it's really bad gum and crap).

So, I'll sort that, but the use of the vehicle isn't likely to become more frequent and therefore we'll have plenty of sunday drives which then evaporate over the next couple of weeks filling the carb with residue again.

Does anyone have an old classic that gets this sort of use? How do you drain an SU? I don't really want to put a drain screw into the bottom of each float chamber, but I don't see any other way of draining the carbs when it's not going to be driven for a couple of months.

Originally Posted by BradC

A neat solution with the minor issue of not having an oil pressure switch. It has a gauge. No idiot light.

Given the infrequent use this will get I had thought about a valve in the fuel line. Given how the fuel pump works, in theory if I held the primer lever up to the stop the pump shouldn't pump and I'll get the same result.

fit a turbo timer on the ignition and then the fuel valve, other than heat in the engine bay and it doesnt take a lot of pumping to keep a carby filled at idle your theory is sound