I have a 1995 maxum with a mercruiser 4.3 vortec webber 4 barrel carb thunderbolt IV ignition system. Recently I had an issue with it not starting. So I replaced the dist cap rotor wires plugs rebuilt the carb new fuel pump and fuel lines, I checked the tank vent and check valve. im getting plenty of fuel. I got it running after finding out My oil pressure switch was bad. Now I can not get the motor to run on 8 deg before tdc. It will run at about 25 deg btdc but nothing close to what it is supposed to be. under load at this timing obviously the motor runs like crap hesitating stalling and just running like crap. What could be causing this??? I am at wits end trying to figure out what is going on. I have verified that the plug wires are in the right order. Please help.