No spark when cranking, spark when OFF

points or electronic ignition? what year boat and motor?

Here's a pic of the distributor, it has part number 3755401, it's electronic obviously from the pic...

I also noticed that my ignition resistor is pretty rusty, this thing that is attached at the back of the motor. http://skidim.com/prodinfo.asp?number=RP119001

Im going to try and take the wires off and clean the connections to see if that helps at all.

I got a new ignition switch and it didnt fix the problem. Still no spark when cranking the motor, but a spark jumps as soon as i shut the key off.

TRBenj wrote: Break out the voltmeter. Check and make sure you have 12V to the (+) terminal of the coil with the key on and when cranking. If you do, then like '79 said, Id suspect either the coil or ignition module is the culprit.

Going to check right now, thanks

Get one of those circuit testers (screwdriver with light inside) and put it on the negative side of the coil and ground the aligator clip. Crank the motor, if the light blinks, then the distributor is breaking fire, if it doesn't the problem is inside the cap, probably the ignition module.

Ok, i just did the light test, when i attached it to either post on the coil i got a solid dim light when cranking.

Tim D wrote: Did it blink/pulse?

nope, i just said it was a solid dim light

I believe most any 'igniter' module firing that coil will see too much current and fail prematurely; lucky if you get a season or two out of one.

The mallory tech told me for what ever reason the Blaster II coils burn up the electronics in the mallory units. There's nothing wrong with the promaster series coil he has other than it's an automotive grade unit, paul uses the same unit on his 62, and I have a marine version of the same thing as well. As long as the dist is wired correctly and the leads wheren't shortened to do it the coil will be fine. It looks like an older Dist anyway and age just took it's toll most likely.

Oh man, i just found this site, by going by the diagnostics test it seems that the module was burned out by high amperage, probably my rusty ballast. http://www.centuryperformance.com/mallory/unitest.asp

installed the ignition module and new ballast, STILL not sparking when cranking, but it still sparks when i shut the key off

79nautique wrote: you sure you have it wired correctly. purple to the pos term gray to neg? how many leads do you have coming from the dstrributor? and where are they connected

Yea, i have terrible news. I did the test on the module again to make sure it was working by measuring the voltage to the - side of the coil and breaking the beam of the module with a credit card, everything checked out fine. I was like hmm, if i break the beam when with the card and voltage drops how come the ring on the rotor isnt breaking the beam. So i tried turning it over with the cap off, rotor doesnt move at all . So my next step was to pull the distributor out to check and see if the gear was still attached, yeap attached fine. Put a screwdriver against the cam gear to see if it was spinning, no go. So i guess i broke the timing chain, i hope it didnt f**k any valves up

79nautique wrote: you would have heard it if a piston slaped a valve.

music was on too, i guess ill find out when i get it running, can i just go to advanced auto and get a chain/gasket for a 84 351, or does it have to be a marine one b/c of the reverse rotation??

79nautique wrote: shouldn't make a difference, just be carefull getting the #1 cyclinder on top dead center so you don't bend a valve, if you haven't all ready.

shouldnt it just be lining up the dots like a sbc? i built the 383 sbc in my camaro, so im not scared by a timing chain, but i've never done one on a ford before.