Just to finish off this thread of engine starting following a complete rebuild - thought I'd add the following regarding the carburetor balancing. Please see photo's as they explain all.
I opted to go for the manometric approach, (as I could make up a system), sure you can buy off the shelf equipment for this but....its all money.
I first had to make up vacuum connectors to replace the vacuum plugs and after experimenting with various liquids I used 3 in 1 oil in the bottles, ensuring that the total volume of oil in both bottles did not exceed the volume of one bottle. Simple throttling valves were still required to slow down the reaction of the oil in the bottles, (these valves are from a fish tank.)
I first balanced carb to carb, then balanced barrels per carb by adjusting the air bypass screws. Yes, you could do everything "all at once" so to speak by having a manometric set up of 4 bottles - I opted to do it just with 2.
Finally I played with the air fuel mixtures on each barrel at the same time adjusting idle speed.
On completion of this I repeated the above process from the beginning and all good.
Problems? "Yes" - but I think relatively minor - I have a seized air bypass screw on one barrel meaning that I had to take that as a "constant" and balance the corresponding barrel to that. Measuring exposed threads it is seized "not closed"
I have accepted this as I am nervous about snapping off the bypass screw in the carburetor body ....
Please note this home made manometric system just shows differential balance - it does not measure anything - which is what I wanted.
The engine sounds very happy, running 180/180/180/170 psi on compression, (the 170 may come up with further running and if it doesn't its ok for me.) - 40 psi oil prressure - temp at 95, with no oil, water or fuel leaks.
Getting on with the body is getting closer - I have been "at this " for some 4 years now.
