Hi Randy:
Since our conversation this morning, I got the engines out to a test stand and was very pleased as to what I discovered! All the HP .40 engines started with one flip and the needle valves worked the way that they were designed. It had nothing to do with the tanks venturm or nva. After thinking about for a few minutes, I asked myself what was changed from yesterday to today? The only variable was the fuel. I was using fuel mixed last Summer and was 10% nitro, 11% synthetic oil, 10% castor oil and the remainder alcohol. The fuel that I mixed yesterday was no nitro, 20% synthetic oil and the remainder alcohol. I mixed this fuel to be run in my Gardner p&c as recommend by Mr. Gardner. I will mix other fuel for my other HP .40, ST etc. engines. This mix will be 5% nitro 22-22 oil and the remainder alcohol.
Perhaps the old fuel went "bad" over the Winter. How, I have no idea.
You were really correct re. the size of the holes in the venturm.
Thanks for all of the help,
Frank McCune