I have a 1986 Evinrude 150 Ser.# 150STLCDC. I have a problem when I go from 3500 rpm to full throttle the motor cuts out like I have let off the accelerator. I have cleaned and rebuilt all three carburetors. I have cleaned all of the electrical connections. I have checked the compression on all six cylinders. I checked for spark and found today at low speed all cylinders have spark but when I go to WOT I lose spark on one bank. I have checked the fuel system completely by the advice of many other posts here, including hitting the choke and spraying fuel into the carburetors when it starts to cut out. Neither the choke or fuel helped. I saw large amounts of fuel entering the carburetors at full throttle. I believe that I have a power pack failing. I went to try and swap the power packs today at the lake but found out the prior owner had hard wired one to the motor making that not possible. I live 30 minutes from the nearest lake and have made countless trips trying to figure this out and any help would be greatly appreciated.