I have a year old 46LA. It runs perfectly on the bench and at less than full throttle in the air. At full throttle it seems like it is surging or varying rpm's slightly. The tank and fuel lines are new. I have heard that air leaks plaque the LA's. Is there a way to check for leaks or to repair them?

try a reseal kit

You could try spraying a little DW-40 around the engine to see if it briefly seals the leak. You would be ablt to tell in the difference in sound.

Ron

Also sounds like it could be fuel foaming. We recently had the same thing going on with an MDS. Ran fine n the ground, get it in the air and couldn't get any reliable rpm out of it. Solution: took the tank out of the wing (Sledge 540) and mounted it to the side of the fuse behind the engine, and problem solved. It was too tight in the wing to get any foam around it. I've got 3 OS .40 La, one .46LA and two .65 LAs and haven't had that kind of a problem with any of them.
Randy