2003 4.3 spark question

Hey fellas, thanks for the add. I’m working on my sisters 2003 4.3 mercruiser which has the t bolt ignition. I’ve replaced the sensor assembly in the dizzy as wel with the cap and rotor. The engine is trying to start I out a timing light on the center high tension lead that feeds the plugs and it lights up when rotating, I move the light over to the left bank and only have spark on the back cylinder, I move the light over to the tight bank and I have the middle and back cylinder sparking. I am replacing spark plugs today but could anything else cause that weird of a miss or loss of spark? The coil that plugs into the sensor assembly has battery voltage going into the dizzy. Ty for any input

Wah! That's sounds almost impossible.

All I can figure is the cap is seriously messed up somehow, or the rotor is broken.

Jeff

Incorrect installation of the cap or rotor....TBolt caps have a not particularly robust locating/indexing system. Also possible that the center leaf spring contact on the rotor is bent.... and there is always the possibility its the wrong cap/rotor????

So it needed up being the ignition coil, primary had correct ohms but secondary read open. Ty for yells time

Muddminnow said:

So it needed up being the ignition coil, primary had correct ohms but secondary read open. Ty for yells time

Click to expand...

Great that u actually ohm’d it out before replacing.lots of coils replaced unnecessarily....