BBC cranks but won't start

[Vintage Eliminator 21]

I've been coming to the Hot Boats forum for several months, right after I bought my boat, and have got tons of usefull info. Been a big help.
Here's where I need some ideas and input.
Went out last weekend and my boat ran well. Went to the ramp today and cranked but no spark. It has an Accel HEI Super coil mounted on top of the distributor. I checked the fuses, that I could find, and all ok. How can I check to see if the coil is bad?
Any suggestions?
Thanks

[Moneypitt]

When you say you checked for spark. I guess you mean at the plug, as you can't check it at the coil output. First, with a volt meter, check for 12v at the plug that goes to the cap/dist. If you have voltage that far all your ignition circuit to there is okay. The next thing I would suspect is the module, those hei deals can just quit like turning off a light switch, (which is why I would never put one in a boat). You should pull the cap and rotor, look under the center of the rotor to make sure you're not grounding straight through the rotor to the shaft. If that is the case there will be a trace or burn mark under the center of the rotor. If you didn't have 12v at the dist, hot wire it directly to the batt + and see if it will fire. Don't leave it hooked up while not running, and don't run it long if it does start. (I don't know how your system is wired, and you could damage components wiring directly). If the motor will not come around, consider changing the ignition system to something very simple, non hei, with standard coil, dist, and either points or a magnetic breaker deal. Those systems can be troubleshot out on the water in the event of a rare failure....MP
PS make sure there is no moisture in the cap from condensation after the last time out.......

[Tinkerer]

Does your boat have a lanyard???
If it is pulled the engine will crank but will not fire.

[Vintage Eliminator 21]

Moneypitt
I'll check out the voltage this next week. I have a dumb question, though. When I take the boat out of the water, I disconect the battery-posative terminal until I go back to the lake with it. Could that have affected anything? Would it be better to disconect the negative?
Tinkerboater
It doesn't have a lanyard. What type of boats are they mostly used in?

[Tinkerer]

Most performance boats have them.
I have made the mistake of walking away from the controlls with the lanyards hooked up and then realized my mistake as both engines died.

[Jordy]

Originally posted by Vintage Eliminator 21
When I take the boat out of the water, I disconect the battery-posative terminal until I go back to the lake with it. Could that have affected anything? Would it be better to disconect the negative?
If you're going to disconnect anything it should be the ground because it won't arc when you hook it back up. Depending upon your setup, fuel vapors in an engine compartment with a good arc and it's going to be a bad situation.
If nothing else, why not fork out the $20 or so bucks and pick up a simple perko switch and a length of battery cable. Quick and easy. It's what I run on both my boats with no worries. Just disconnect the negative from the battery and run the switch in between.

[Moneypitt]

If reconnecting the positive terminal creats a spark/arc, there must be a load of some sort in the system. However, the spark will still be created if the negetive terminal is the one used to disconnect/connect the system. All it takes is the connection to complete the circuit, positive, negetive, makes no difference. Now, back to the ignition problem. I can't see where disconnecting the battery would have any bearing on your ignition problem. Moisture in the cap will do funny things, as will moisture in any electrical component. Boats are very touchy in the wiring, there is no common ground like in a car with a frame, so everything must have a ground source as well as a positive source. Any little resistance in the circuit, as in bad or corroded conection, anywhere in a given circuit, can really screw things up. Do your voltage test, and work from there. PM me if you like, I'll try to walk you through this...........MP

[Vintage Eliminator 21]

Finally got a chance to check the wiring. It was 12v coming from the red wire to the coil. A friend of mine that owns an auto shop had his mechanic check the coil and according to the test procedure, it checked out ok.
Is there any way to test the HEI module?
I found out what the load on the elec system is. The hour meter cycles. Not sure if it's counting the minutes, but it cycles without the ignition on.
Thanks for the help!

[mickeyfinn]

On a car you should always disconnect the negative if you are going to unhook something. This is so there is no ground to the vehicle frame which prevents you from arcing from positive to ground if your wrench comes in contact with the positive and the fender or other ground. In a boat I don't think it matters unless the battery is extremely close to the engine and you might accidently arc fire from the positive to the engine with a wrench. The hour meter should not be putting a load on the system unless the ignition switch is on.

[Oldsquirt]

Originally posted by Vintage Eliminator 21
Is there any way to test the HEI module?
There is no real test for the module. The typical scenario in diagnosis is to verify everything else is OK, then replace the module. Kind of sucks. As a tech, I used to work on a lot of HEIs so I kept a spare module in my toolbox to confirm a "module" diagnosis. They only cost about $35 and are held in with 2 screws.
There is another item in the distributor that does fail and that would be the "pick-up coil". This wraps around the distributor shaft and sends the trigger signal to the module. The wires on this item are very small and do break. Disconnect it from the control module and perform a resistance test with an ohmmeter. I'm afraid I don't recall the exact spec for this but would expect it to be in the 150-250 Ohm range. Perhaps your friend could give you the exact number or test it for you. Obviously an "open" would indicate a bad pick-up coil. Replacement requires total disassembly of the distributor and a reman unit would be more cost effective.