mercruiser 165 no spark from coil

when i recieved my mercruiser it would not turn over, had 4 inches of water on deck (plus the entire hull was holding water), the apholstry was destroyed and it was filled with trash but the engine was in good shape and you cant complain when its free so i cleaned it up. my dad so happened to have the mercruiser manuals already so after a few days of rewiring i managed to get the starter to turn over and even get a spark at the plugs. since murphys law never fails i made the mistake of leaving the battery on the charger hooked up to the boat with the key in the on position when i went to bed that night, you can imagine what i found when i returned to my project the next morning (w/ $250 in parts for the fuel system). well the ignition coil burned up along with the points and resistor wire. aftertalking to several mechanics i have yet to find what the problem is. i replaced the points, condenser, coil, and have added a ballast resistor to the resistor wire. i see that there is 9v getting to the coil and have done a bench test on the coil it passes with 1.8Ohms Primary and 10,400 Ohms secondary. i have replaced and checked the wiring a million times, have bypasses all of the neutral safty switches and cant think of much else i can do. if anyone as any suggestions i would appreciate anything you can think of. its killing me because i know if i hadent been a bone head i would have been on the water 2 months ago!

R/
turdcraft

Re: mercruiser 165 no spark from coil

1) Check to make sure you have voltage at the coil with the ignition on. You should have 12V with points open and 7-9V with points closed.

2) Make sure you have your dwell set properly.

You can manually open and close your points with a screwdriver and verify that you have spark from the coil while holding the high tension lead about 1/4" from ground. This will test your coil.

Re: mercruiser 165 no spark from coil

Im confused a little to you "added a balast resistor to the resistance wire." Did you replace the resistance wire with a balast resistor or add a resistor. If you added you have too much resistance as the wire + balast resistor will lower your current below where it can work.

You should also have a bypass wire from the starter to the coil so that the coil gets 12 volts when starting. make sure it is connected properly.

Re: mercruiser 165 no spark from coil

I agree with Doernuth. You need one or the other...not both.

Re: mercruiser 165 no spark from coil

tank you for your responses. as far as my resistor wire goes, it was fried along with everything else and isnt providing any resistance at all anymore, a problem that isnt uncommon, thats why i have the balast resistor. im not showing any spark at the points when i open them i have set the points to
.22mm.