some of you may have read my post from 2011 (france trip) when Ruby - our midas coupe mk3 had power loss on an exceptionally hot day when cruising along a french motorway - power faded and engine stuttered until speed dropped from c 65 to c 50 then ran smoothly - happened a couple of time and we decided symptoms were consistent with fuel starvation (engine never died) and we decided most likely problem was excessive heat under the bonnet and fuel lines (which on Ruby are rubber and ran very very close to exhaust downpipe) gettting too hot - fuel vapourising and reduced supply hence power loss.
Following advice we bought a rather neat polished stainless steel heat shield which we bolted on and which sits under the carb and we ran the fuel pipe between (above ) the heat shield thinking this would prevent it getting too hot.
All since been fine - hurrah - until past fortnight.
Have twice in recent very hot weekends - taken Ruby for a run and each time recurrence of the French problem - once Ruby is upto temperature (and by that I mean warmed up not overheating ) and cruising on dual carriageway - had same loss of power and stuttering engine and speed dropped off then at lower speed ran smoothly .
Have replaced fuel in line filter - in case this was restricting flow (but why only on very hot days?) and bought new (rubber again) fuel pile which I have run from engine mounted fuel pump -back away from exhaust down pipe and circuitous route away from exhaust to carb- problem still there on very hot days so puzzled as to what it is?
Have bought exhaust heat wrap which I will fit in next day or so round downpipe (and perhaps also wrap around fuel pipe where closest to exhaust) in hope that cures it .
So problem only has ever occured on really hot days- no excess temp on gauge - hoping that exhaust wrap will cure it but any ideas appreciated
one bit of good news is that in UK exceptionally hot days truly are exceptional and rare!
thanks all