My gremlins are back

I only ever saw those with positive earth systems. When negative earth started becoming more common they marked the coil + & -.

Stood for SWitch and Contact Breaker.

My mistake should have read that better Pos earth system,

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jim Warren saying something like:

Classic Moggy fuel-too-hot and evaporated symptoms. There used to be a heatshield you could fit under the carb and deflect some of the exhaust heat away from it. Many left the factory with one on and it usually fell off somewhere in the following years.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jim Warren saying something like:

Something else occurs - this is a bastard of an intermittent fault to find unless you've suffered it once. The flexy wire in the distributor gets heat hardened and fractures internally, causing intermittent stoppages - when you test it, it tests fine, but fails in use. As a get-you-home you can use fine multi-stranded wire, but the right grade of heatproof multi-strand is to be found from the likes of RS, CPC, etc.

It might possibly be a contributory factor to why the engine stops in the first place, but it doesn't explain why it needs at least an hour to cool down before it starts again. In that time, it gets completely cold, so any evaporation would have been resolved long before.

Jim

It this something that can be tested with a meter? For instance, if I measure the resistance between the two ends and waggle the wire, would a faulty wire show a varying resistance? Alternatively would a faulty wire show a markedly different resistance between hot and cold?

Jim

I think your correct and that after you stop the fresh petrol should be pumped back and the float filled again.

What I would do when the car stops.

Check for spark at the plug pull a lead off - turn the ignition on and push the started solenoid under the bonnet.

NO - lift the distributor cap and check if there is spark at the points - you can flick them open or with a screw driver and they should spark across with the ignition on. Are the points dirty - new condenser required.

NO - them go further with the electrical system and see if there is power to the coil with a test light. Could be a dry solder in the bullet ends dirty joints etc.

if YES there is spark - start looking at fuel. Observe its not flooding.

Pull the fuel line off and see if the pump is delivering fuel. Ignition on.

If not start with checking power to the pump, the pump could be stopping and needs either replacing or new points (electronic now) If points hit it with a hammer and get it ticking again - shock it back to life,

Does it have an inline fuel filter. or is there one in the fuel pump?? Can't remember if there is one in the SU pump in the MM. Is that dirty.

You have not mentioned what pump you have if its the original SU or aftermarket???? What pressure is it running at (should be about 1.5 psi with isn't much)

I've had this sort of thing on 2 occasions on my frogeye, one time it was the point heal wearing down so the gap was virtually non existant. The points were about a months old and I had never had a set wear like that before. The engine started and ran fine until hot such as when sitting in traffic then would falter and stop, restarting was fine after then engine had cooled. The 2nd time was a new coil that failed when hot, restarted fine after cooling down.

In message , Rob writes

Also:- NO (a second test) - pull off the coil-to-distributor lead, and see whether there's a good spark to earth from that. We had a situation on a Minor MM where there was no spark from any plug lead to earth, but a perfectly good one from the coil lead. The spark was earthing down in the distributor - a replacement one solved the problem.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jim Warren saying something like:

I can't say for sure, since it only happened to me the once. Best way is to take it off and pull it while testing it. After the first time I made a point of replacing the flexy wire on every car after that. You might find on as NOS, but as I said it's easy to simply use a bit of HP.