I have a question for anyone that can give me an explanation.  The 100 series Veco .35 is a good 424 running stunt engine, but the 100 series .19, which has, as far as I can determine, the same port timings is anything but.  No matter how rich I set it, once in the air the thing goes beserk and just howls around.  Can they be tamed?  I have tried lowering the compression with head shims, but the only difference that I could see was that it became (a lot) harder to start.  This isn't just in one model/tank setup.  It has been in several planes with different tanks and it always behaves the same.
I would like to know why.
Charlie