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Jim's Problem Minor

I was giving this some thought on a long drive (Dumfries to Wensleydale and back) and here's what I came up with ...

To run, a nice simple old engine like the Minor's needs ...

a) Compression

b) Fuel

c) A spark and

d) For all of these to happen at the same time

So the next time it plays silly buggers, I'd suggest that he ...

a) Does a compression test, in case valves or head gasket, are doing something silly

b) Checks that the throttle is opening, the choke isn't on, the piston is moving, the dashpot is dashing, that fuel is coming through from the pump, that fuel isn' t dribbling out the manifold drain (the Minor has one, from memory) and if it passes all these. tries a bit of Ready- start (why can't we buy "Start You Bastard" here?).

c) Checks for a good fat spark at all four plugs

d) Checks the timing

(Actually I'd do the compression test last, but I'm too lazy to reorder the above).

Ian

Reply to
Ian
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and air, mixed in the right proportion

It has been raining most of the weekend, so I didn't bother taking the car for a long run, because I would have got soaked looking under the bonnet testing things.

But I have been musing too. This was my approach:

Take the car on a good run. Instead of switching the engine off, disconnect the fuel pump electrics and wait till the float chamber empties and the engine stops. Switch off the ignition and reconnect the fuel pump. Leave it 10 minutes.

Now apart from the fuel, this is exactly the scenario where it wouldn't start. So when I turn the key, the petrol pump will refill the float chamber while the starter motor is turning the engine. If the engine starts, I am looking for a flooding problem caused by the spring in the petrol pump continuing to deliver fuel while the ignition is off. If it doesn't, I will have to think again.

But my guess is that either the needle valve isn't seating properly or the float is set too high. Because pretty well everything else wouldn't make so much difference whether the engine is hot or cold.

Jim

Reply to
Jim Warren

Might be worth rigging a bottle of petrol for gravity feed to prove if it's a pump or evaporation problem.

But my bet is still ignition. Have you got a dwell meter?

Reply to
Dave Plowman (News)

No I haven't. Multimeter and timing strobe are all that I have for the electrics.

Jim

Reply to
Jim Warren

Swap the strobe to number 4 and see if it hits in the same place. Same with # 2 and 3 place a mark on the pulley and see if that hits in the same place.

Irrespective, 90% of problems are electrical and when this has been sorted then you go looking for other things.

Reply to
Rob

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