yamaha 250 cuts out

[braceyourself]

My port engine, 2006 250 4 stroke cuts out in idle. If I immediately put the engine in gear it runs fine all day....until I try to trim the motor up while running...then it cuts out again. I checked all of the batteries for stbd and port engine and they all tested fine. I thought for sure that I had a dead cell. Any suggestions? thanks!

[boats.net]

May have a low voltage problem, voltage at engine should match battery voltage and when activate trim switch or starter voltage at engine shouldn't drop below 10 volts.