coil failure?

[jp02ti]

how would a failing coil present itself? what would the symptoms be?

the blue book is unclear, and the search has failed to yield results.

thanks,

Jon

[guibop]

http://www.clarks-garage.com/shop-manual/ign-04.htm

[JFT]

When one of mine failed, its symptoms were rather like running out of fuel. Sputtering and jerking which got worse over a very short distance, then silence. Well, then the auto club, the trip home, then the new coil. Don't know why it should have been so, but in my case, it was.

[PeteinMissionViejo]

2nd the running out of fuel / fuel pump failure. I even replaced my fuel pump. It was the coil.

[Guest Anonymous]

how would a failing coil present itself? what would the symptoms be?

the blue book is unclear, and the search has failed to yield results.

thanks, Jon

Have you tried searching beyond the forum? Ignition coils are found on many different 2 and 4 stroke engines around the world for 100 years.

What symptoms are you experiencing? Weak or failing coil can mimic a failing fuel pump, as others have mentioned. Bad ignition condenser can also result in weak spark and intermittent firing similar to running out of fuel.

Coils are "coiled" wires often encased in oil to protect the wiring and keep it cool. When coils are working, they produce heat. Coils generally fail when the fragile wiring is damaged. The damage can occur with mishandling, vibration, old age and excessive HEAT. Coil's that are kept cool can function fine until they heat up and start malfunctioning. There is a reason for the ballast resistor. Startup is assisted with maximum spark. Ballast resistor is bypassed to enable coil to produce maximum spark. If coil receives full 12v for too long, guess what? It overheats and dies. That is why the ballast resistor is installed to reduce voltage at all times except starting.

hth.

[RussTii]

Jon, if you'd like to swap out the coil to identify the failure I have a couple of spares. I also live in Lawrenceville. Gezon@aol.com

[jp02ti]

thanks everybody. i am experiencing missing and bogging, which does indeed feel like fuel pump failure. the car is fine when idling, and reving when in neutral. i bogs when accelerating from cruising, and stumbles in mid-range. thus far, i have: replaced fuel pump, points & condenser, wires, cap and rotor, cleaned all jets, removed air filters, reset timing with light, set dwell with meter, changed head gasket (oil leak...), re-checked timing chain position, pulled all new ignition wires, cleaned/changed/gapped plugs.

coil seems likely now. I don't have a ballast resistor, i don't that I ever did. is it true that with certian coils it is not required?

Russ, I'll e-mail you, your offer is greatly appreciated.

Thanks,

Jon

[Guest Anonymous]

t I don't have a ballast resistor, i don't that I ever did. is it true that with certian coils it is not required?

Yes: blue coil has built in resistor. See FAQ on coils.

Never hurt to swap coils but your problem might still be something other than coil. You are aware that you can test a coil with an ohmmeter? Search. And some electrical shorts can be difficult to detect. Take a close look at the engine running in a dark area (night time) you may be amazed at what you see after your eyes have adjusted to the darkness.

If your carb is jetted too lean or on the edge of too lean, you can be getting what is commonly referred to as a lean misfire. Ambient temperature changes, change in ignition timing can push things to the edge.

Thinking out loud.