Some Comments About Coils

[Boilerbob7]

Ignitor

Thanks, I see I need to do a lot of crawling to find out what parts are on this engine and to determine if it's an early or late model. All I know now is that itruns really nicely.

[ndutton]

Blitzkrieg

Bob,

Where did that 190-V2 ignitor part number come from? I couldn't find any reference to it regarding coils anywhere. 1939 radial engine Focke-Wulf 190-V2 - Ja-wohl but coils - Nein.

[msc6312]

engine won't go off with ignition switch

Late last season my engine wouldn't shut off when I turned the key back in the ignition. It wouldn't even go off if I removed the key altogether. I ignored the problem for the duration of the season and used the choke to shut off the motor. Yesterday I fired up the motor for the first time since last year and the problem persits (imagine that..the engine didn't fix itself over the winter). Where do I start to figure out why the ignition will start but not stop?

[ghaegele]

I think you have one of the more simple fixes in front of you: replace the starter switch.

Good luck

[hanleyclifford]

Late last season my engine wouldn't shut off when I turned the key back in the ignition. It wouldn't even go off if I removed the key altogether. I ignored the problem for the duration of the season and used the choke to shut off the motor. Yesterday I fired up the motor for the first time since last year and the problem persits (imagine that..the engine didn't fix itself over the winter). Where do I start to figure out why the ignition will start but not stop?

Do you have access to an electrical test meter? You need to test voltage at several points to diagnose the problem.

[ghaegele]

Do you have an ammeter at the engine panel? If so, is it on all the time whether ignition is on or off? If yes, you have a bad ignition switch, since it is very unlikely you have a short going to both the coil and the ammeter/alternator. (Actually, all the meters should be off when ignition is off, not just ammeter.)

The only possible reason your engine is not turning off is because you are not cutting power to the coil. Electricity runs from your battery or battery switch to the large bolt on the starter solenoid, and from that bolt it powers the ignition switch. The ignition switch in turn energizes the coil allowing the engine to run (and connects to the ammeter/alternator), and also engages the starter solenoid when turned to the start position.

You are getting power to your ignition switch. You are getting power to your coil. And you are getting power to your solenoid since you can engage the starter and start your engine. The problem, then, is either your ignition switch not cutting power to the coil when you turn it off, or a short circuit (or incorrect wiring) somewhere else that is continually powering your coil. To test your switch, disconnect the wire from your coil to the ingition switch at the ignition switch. If you can successfully start your engine the problem is somewhere else. If you can only engage the starter but it won't turn over, replace the switch.

[ndutton]

There are only two possibilities, the ignition switch as previously mentioned or a short between unswitched 12V+ and the ignition circuit (possible but rare). Another quick test would be to remove the wire from the IGN terminal of the switch and test for 12V+ at the coil+ terminal with the battery switch on. Test=yes=short somewhere, test=no=bad switch.

Another side effect of this problem is the possibility of coil damage. They don't like to be energized without the engine running and unless you've been religious about immediately switching the power off to the engine system after flooding the engine to die, the coil has been stressed. They don't cost that much, after resolving the ignition switch or short problem I'd recommend a new coil.

[ILikeRust]

I think you have one of the more simple fixes in front of you: replace the starter switch.

Not necessarily.

I had this exact thing happen to me last year. Sometimes the engine would shut off when I turned off the switch; sometimes it would just keep running as if nothing had changed.

I dug around and found several abandoned circuits that were still connected to hot leads, but terminated out on space, not connected to anything.

I pulled those surplus wires out and the problem disappeared. I never did determine exactly which wire was causing it, but clearly I had stray current getting to the coil somehow.

Of course, I figured that out AFTER I bought a $28 switch and installed it and discovered that it did not fix the problem.

[StephenGwyn]

Interesting. I replace my coil every 2-3 years. I replaced it this spring when I put in a electronic ignition for the first time. Yesterday, it burnt out. I figured this out after replacing everything in the distributor, because previously, the coil had never come close to having any problems.

SG

[Dave Neptune]

SG, did you happen to leave the key on for a bit? Easy to do.

Charging levels and resistors, time to do some checks.

Ran EI for 34 years and had one coil get weak and replaced it~that's it never cooked one.

Dave Neptune

[Marian Claire]

Did you do any testing of amps output from the coil? Sounds to me like the classic change to EI and the accompanying different dwell time, compared to points, slightly changing things and causing issues for the coil. For me failure was caused by simply removing a few feet of wire and a connection. A few tests and use of Neil's formula may be useful.
Dan S/V Marian Claire

[StephenGwyn]

@Dave
If by a bit, you mean 10-15 seconds, then yes. If you mean minutes, then no. The engine hours counter ticks every 6 seconds when the ignition is on. It can take me 3 ticks to remember what the noise is and turn off the ignition.

As for EI cooking coils, I'm referring to the sticky post by Moyer at the start of this thread.


@Marian, No, I replaced the coil and went home. I'll do a full post-mortem next time I'm on the boat. I also plan, as our host suggests, to get an oil-filled, metal jacketed coil.

Stephen

SG, did you happen to leave the key on for a bit? Easy to do.

Charging levels and resistors, time to do some checks.

Ran EI for 34 years and had one coil get weak and replaced it~that's it never cooked one.

Dave Neptune

[Marian Claire]

I am not the best at this but what you need to know is the voltage being supplied to the coil. You also need to know the resistance of the coil. That needs to be tested with the coil disconnected and undamaged. IIRC the bottom line is that you want to be delivering less than 4 amps to the EI.
Dan S/V Marian Claire