This engine has low hours, new plugs, new t-stat, new impeller, new lower unit oil. It started right up. It ran for about 10 minutes a full speed, then ran for another 10 minutes at only 1/2 speed, then died totally. Gas and oil were fresh. Tried to pull start with spark plug removed and grounded to the engine block. Saw spark on only 1 cylinder. Seems like the ignition coil?? Please give me your suggestions. Thanks
