View Full Version : Ballast resistor for coil

09-07-2012, 03:42 PM
Does anyone know if the electronic ignition on a 91' Indmar 454 require a ballast resistor for the coil? I have electrical problem starting the engine and installed the skidim replacement for the factory prestolite distributor. I cannot get engine to fire and was wondering if the 30 amp reset on rear of engine was also some type of resistor for the coil. Everything I read on electronic ignition says they need a ballast resistor, but I cannot find one and the original had electronic ignition.

09-08-2012, 01:54 PM
the 30 amp is a reset for everything, i am unsure about the 454 ignition system but ballast resistor for the other engines is .8 ohm. the resistor itself will not prevent the coil and distributor from working unless its broken in 2 pieces. Whats the voltage at the coil with key on? no resistor should be 12v with resistor about 7-9v. if you have volt at coil and you assume the distributor is operating properly then prolly have a bad coil. this msd coil has the ballast resistor sold with it. http://www.summitracing.com/parts/MSD-8203/ otherwise here is ballast resistor http://www.summitracing.com/search/Part-Type/Ballast-Resistors/?keyword=ballast+resistor&kr=ballast+resistor

09-09-2012, 02:19 AM
You can also buy coils with an internal resistor. Just put on on my 1973 to save the trouble from having wire up the ballast resistor. I have had two mc with coil trouble. One was with a ballast resistor that was wired backwards...easy fix. Coil would get hot as a stove eye and would not restart til it would cool down. The second was my 1973. Someone had replaced the points with a Standard Points Replacement Kit and did not put a ballast resistor on it. It would run fine for a bit and then cut out and not run well and foul the plugs out. Checked the coil and it was bad. Bought an internally resisted coil at Advance Auto Parts for 17 buck. Runs like a champ. The old coil would get hot as a stove eye and it deteriorated. I used this website for the parameters to see if it was bad. It test as so. http://www.international-auto.com/fiat-lancia-electrical-system/how-to-test-an-ignition-coil.cfm Good luck. Paul

09-12-2012, 09:42 AM
What is the best way to check if your coil is wired up backwards? Did you have hard to start issues cold and hot while it was wired up backwards??

09-12-2012, 09:50 AM
Look at the wires going to the coil. One terminal is marked +, the other terminal is marked -

With the key in the run position, determine which one has power to it.

09-14-2012, 10:38 PM

09-15-2012, 10:59 AM
You're welcome. Good luck.