i have a gms 61 that is almost new in my edge 540.
the engine starts right up,it idles great and revs just fine too.(11,500 with 12-6 nylon prop and bisson pitts exhaust).

the trouble i'm havin is the engine dies when i put the plane vertical on pre flight check.

this has happened only after it had 4 problem free flights and preflights.

is this a too rich problem or something else.

any help would be great.

thanx

mv-warbird

make sure the clunk line is not to long and closing itself off aginst the back of the tank when pointed up. Tank position both height and distance can also cause this problem... make sure the tank is as close to the engine as you can get it and the centerline of the tank is with in 1/4 inch of the carb centerline...
some times pitt's mufflers won't give enough back pressure to the tank... this most often will show up on a nose up test and vertical up lines... if the engine won't richen up enough to pass a nose up test plug/pinch off the pipe closest to the exhaust port on the muffler and try again.

John