UPDATE 17/09/2020
Well! Nigel's points arrived and, yes, plastic blister packed the same part number and manufacturer as my 5 sets purchased from Comerfords!
So, I didn't bother changing the modified set for the new set. Checked the timing through for the umpteenth time and persuaded myself that I had this part of the spell correct.
When asked for a points ignition condenser/capacitor the auto electrician looked at me blankly and suggested that I should try a motor factors, as all their stock of points ignition related items were thrown away at least 5 yeras ago when they moved.
Not surprised, but!
The factor came up with the item, but as it tested the same as the one fitted, they weren't swapped.
Rebuilt the Amal MKI concentric 932, with a white plastic float (1mm below top of bowl casting when sealing), viton tipped aluminium float needle, 3.5 anodised slide, 2 banded 4 stroke needle, clip in the middle groove of three, 106 needle jet, 220 main jet, the pilot jet is the drilling in the carburettor body, not a replaceable brass jet (all used before the rebuild ,with no problems and in good condition) and the fibre washers replaced with homemade viton 2mm depth washers (no more weeps and seeps). Air screw at 1.5 turns out from seated, slide screw resting on the bottom of the slide, as it rests on the bottom of the carburettor body venturi. The carb is mounted on two alloy stubs, with 38mm of marine reinforced fuel hose between them and secured with 'Jubilee' clips.
After a lot of kicking managed to get the engine to run and achieve a high tickover ~1,500rpm, with the air needle at 1 turn out from seated and the slide screw 3/4 turned in from rest. A slower tickover can be achieved but this is not lasting and the engine stalls and 'spits back' through the carb (sign of weakness)
From cold, the engine requires a 'good tickle' and will then fire up and run, but any whiff of throttle results in a spit back through the carb and stall. After 3 or 4 of these short bursts the engine can be held on the throttle at ~2,000rpm and warmed through ( less than 100 miles on rebuilt motor using Morris SAE40 oil) factory exhaust pipe, combined with a gutted 11/2" (38mm) inlet I.D. Gold Star pattern exhaust, with a total length of 271/2" (700mm) and outlet I.D. 17/8" (48mm). There is nothing inside the shell (blown away by the engine, many years ago!) and used in this condition before the rebuild.
Went for a good cross country run today and after ~10 miles stopped to adjust the carburettor. The engine refusing to settle to an idle or run below ~2,000 - 2,500rpm even when running in the bottom 3 gears. Reduce slide screw lift, adjust air screw to stop spit back through carb and then readjust slide to achieve a steady tickover ~1,300 - 1,500 rpm. However, once underway again the revs rise and the whole scenario is repeated.
Rode the last 30 miles home, through town and country with the engine revving at ~2,000rpm. That is now 200 miles run with the condition.
An oil change after 50 miles, showed no slivers, flakes, or lumps of metal and nothing picked up on the magnet.
The engine picks up, once hot, without any spitting back through the carburettor and revs up to ~4,000, without any hesistancy, I suspect that I may need to increase the main jet size, but until I can get this idle sorted out there seems little point.
The plugs are either a NGK B7HS or a BR6HIX, I have also used a B6HS, the latter two heat ranges recommended by NGK and the first by Nigel. They appear to have no effect upon the reving and all have a light tan colour on the insulator.
QUESTIONS?
Is engine vibration causing the fuel to froth in the float bowl, due to a harmonic caused by it's remote mounting?
Should I use a carburettor with a replaceable pilot jet (25), rather than the drilled gallery (20?)?
Should I try the Amal MKII 2932 again, with the same settings as the MKI? I am not sure if a 31/2 slide in the MKI has the same effect in the MKII, they being very different instruments.
Should I substitute the Goldie for a short 'Supertrapp' meggaphone with removable disc diffusers to increase or decrease the exhaust pressure waves.
Should I substitute the Goldie for a gutted short reverse alloy cone megga.
My apologies if this bores the pants of anybody, but if it helps another at some later date, it will not have been in vane.
Good health, Bill