The ridge isn’t large at all and would not raise my eyebrow if I were not looking for a source for puddling but is one of the areas that I smoothed out on mine, you can see it in the pictures. I don’t think this area is the whole problem and my not need to touched at all. Ralph Cunningham modified a different area that may be the bigger contributor. Both of our mods had positive results but were not perfect, I think we’re on the right track though.

After further studying of this crankcase and re-reading Ralph’s descriptions I think I understand what he did. So in a bold move I installed a REAL drain for the puddle. I had to think about this for a while because I could not duplicate the dying on my test stand. Engines mounted on it are at a 90 angle to gravity, on a plane, on the ground, and in slow speed flight they are at a higher angle of attack. The ledge right below the reeds would then be able to hold a fair amount of fuel, definitely enough to kill an engine at a low idle. I will modify the way this engine is mounted on the test stand and run it later today.

Just this morning I got the first email from a customer that is having this problem and is sending his engine back for repair. If my testing goes the way I hope, I will install the drain only on his engine and test it.