35 replies to this topic

[bluequinn]

I did some more testing and have more information

Firstly, I have a big fat spark at the king lead from the coil, and sparking at the points, which are opening and closing as they should. 

But I have zero spark at the plugs. I tried another known good spark plug and got no spark there either. 

 

I'm guessing this means a failed condensor, yes?

 

My thinking is to go straight for an electronic ignition conversion and do away with the old setup.

 

My second discovery was that i am sometimes able to crank the starter motor by simply waggling the wires that lead to it behind the grille. I must have a short in that section of the loom. Not ideal. However that's a secondary problem.

[gazza82]

If you get a spark from the king lead then the problem is probably the distributor cap or rotor arm.

 

The small carbon brush is still there I guess? Transfers the spark from the king lead via the rotor arm to each plug in turn .. they can, and do, drop out!

[Ethel]

The points look a tad burnt to me, but that's just from a photo & if they've been in there for years that could be why as much as a specific fault. It would suggest the condenser, but if you're getting a good spark out of the king lead, maybe not. The points & condenser are service items, so just changing them would have been routine in this situation - BUT, there's enough dodgy new parts out there so  you should at least hang on to the old ones if you do replace them in your search for a cure.

 

As Gazza says the distributor cap would be the prime suspect from your last post. It's another item that's worth carrying as a spare. You can do some confirmatory diagnosis by fitting each plug & its lead directly to the coil to see if they spark. Not too necessary, but if you're going to order parts online it could save you making an extra order.

 

Just leaving the filler cap off would eliminate a blocked fuel tank breather & a good start with the fuel system is to take the fuel hose off the carb & crank the engine to see if it's pumping fuel. Catch it in a bottle & you can use it to splash a little directly in to the carb's air intake to see if the engine catches on it. As has already been said though - always check the ignition first.

[Steam]

Forget the condensor, electronic module or any fuel issue until you have spark at the plugs. As said above cap or rotor arm. Once you have a good spark at the plugs you can then start to sort it.

[Mr Piggy]

Could also be rotor arm. If you crank it,holding the king lead about 6mm above the brass part of the arm the spark should not jump to it. If it does, the insulation on the arm has failed. If the rotor arm is good the spark will try to go somewhere else, like up your arm! So plastic pliers are recommended.

[68+86auto]

It is not recommended to test electronic ignition systems with the leads disconnected.