Not sitting level + drippy carb = greater risk of booms. But I've had it hydrolock on me on the uphill side, too. A straight cross tube will do just as you say but that wye under the carb has a kind of divider in the center and a drip will still go to the uphill side if it's only a mm off center that direction. There's no low spot to catch it between there and the intake valve, either.
In any case there is far too much liquid gas going down there. If I forget to turn off the petcock it will almost drain the tank. Now, I just adjusted the float valve to try to knock that out. I'm not sure if I got it right yet but I'm going to conduct an experiment before I put the manifold back on. The carb can hang right where it would if it was on the manifold and I will see if it will still drip.
The other thing is the accelerator pump. When on my very short test rides if I crank it, it bogs down. I have to ease off the throttle. I think that big shot of liquid gas from the accelerator pump is doing more harm than help. That relatively large carb doesn't need it. I am going to disconnect it for my next test ride and see if it helps.
I thought that wasted spark is what's setting it off but I don't see how. The gas shouldn't be getting to the spark. Both valves should be closed during both sparks. I welcome explanation.
