I had the same problems with my LA's. I found that the real problem was the remote needle setup. On one of the .40's I replaced the carb with a OS FP .40 carb (I believe the Tower .46 carb also works). On the other I removed the plastic fuel nipple on the stock carb and made a bushing to press fit in it which was tapped for the needle assembly off of a FP. Both worked great and ran inverted with no problems. Adjustments are more precise too. For some reason the remote needle setup would siphon really easily and you had to get the tank low and once they got a little wet they would always hydrolock. Never had a problem after ditching the remote needle.