Need some help. I have a 1995 Mercruiser 454 with the Thunderbolt iv ignition system. First, I will set the timing at the recommended 8 degrees advanced. The engine will idle perfect at 750-800 rpm. I give it gas and it bogs down and backfires throught the carb. Nice. I then can advance the timing until the engine will accept the throttle without much hesitation. I put the timing light back on and it reads about 26 degrees advanced at idle. I rev the engine and the advance appears to be working and advances fine. So I figured if the timing really is at 26 degrees, it will struggle to roll the motor on restart. I cut it off and it fires right back up no laboring. Am I not setting the timing correctly? Could the timing mark on the balancer be off or the timing pointer be that wrong?
While I have your ear, The ignition box or module or whatever the correct name of the box that botlts to the port manifold. Mine is shaped like a box, a lot of what I see online are small modules on a triangle shaped plate. I also have a 350 in a Larson and it has the small module. What is the difference and can I use the smaller module to replace the box? I hate electronics so I would like to carry a spare with me. Thanks for all your wonderful advice!
While I have your ear, The ignition box or module or whatever the correct name of the box that botlts to the port manifold. Mine is shaped like a box, a lot of what I see online are small modules on a triangle shaped plate. I also have a 350 in a Larson and it has the small module. What is the difference and can I use the smaller module to replace the box? I hate electronics so I would like to carry a spare with me. Thanks for all your wonderful advice!