Long time to answer, but strange outcome. Back in the summer I had a new diaphragm clutch fitted along with a better hydraulic cylinder for smooth actuation. It was after this that the starter motor stopped engaging. What I found was that a plate had been put in between starter motor and Bellhouse !!! Now plate taken out and all sorted.
You will remember my saga of falling in the garage and braking the electronic distributor and I have bought the new 123 blue tooth version, which I am pretty happy with. Set at 10 degrees static and tickover of 600 - 700rpm
But now the next question and thoughts.
Also back when I had the car on the rolling road, the tuner said my throttle shafts were a bit worn, so I took the two HD8’s to Burlen SU and had new shafts installed and all new butterflies etc.
As you know the all needles are virtually the same on the top three stations of 1/8” each station down, which is where the tick over is.
I have tried UM, UO, UVO and UN. Obviously none are any different on tickover but vary on mid to full throttle. Except the UM’s which are far too lean with only two HD8’s and will not allow the engine to fully rev. I have all the SU comparison books, showing sizes.
Finally after my long winded ramblings, I have a question and strange observation. Normally in theory on an HD8 you wind the jet down 2 1/2 turns which is about 0.047” and the air volume screw up and out about 3 turns. I have found that to get the car to tick over reliably I need the jet down about 4-5 turns which is 0.08” to 0.10” and the volume screw up and out 6 turns. I have checked the float level and is correct with a 7/16 bar and good pin valve. If I have the settings as original recommended and I put two closed fingers across the open throat of either carb, the tick over increases slightly and smooths out indicating it is too lean and my fingers are acting as a partial choke ?
My combination of jet and volume screw setting, does help a bit with point where I have switched off the starting carb and before the engine is really hot. When it is hot not much problem, just the bit in between.
Also interestingly, where ever I have the little nut set on the starting carb hisser, it takes a bit of churning to get the car to actually fire easily and then it will not straight away go 1,000rpm, until I give it a bit of a blip on the throttle. My starter carb is of the type that splits into two tubes then six tubes into the manifold. I have had it all apart and cannot see any fuel or air leaks
This theory of lifting the piston 1/8 inch to test mixture does not work as in practice, as if I do that the engine stalls indicating a lean mixture, which surely it can’t be ?
If I statically Rev car and blip throttle, no black smoke.
Once the car properly hot and off choke it goes very well, so not really a big problem, just trying to understand the strange settings.
Sorry for long post !!