idle problem cured, now I have a 'no acceleration' problem...

[Highwaylass]

Maybe it's time to give up!

I had issues last year with a refusal to idle. Ended up rebuilding the cylinder heads and that seemed to cure it.

Last weekend I was on the A45 when suddenly the engine started to 'kangaroo.' We limped on for a bit but had no power at all and had to call recovery.

I've replaced the points and condenser and set the timing, also new plugs (gapped correctly) and leads.

I've also changed the primary jet to a 125 based on a previous conversation with Ken. (it's a 21-24 Solex)

Is my first step to change the jet back?

I'm losing heart that this car will ever run properly

[Geoff Ryall-Harvey]

SIze of the jets should just affect performance throughout the range - maybe you'd get some flat spots on acceleration and be down on power a little. This doesn't sound like that at all.

Was it popping and banging? That would be the symptoms of a duff condensor. Did the points have "whiskers" on them? Another indication that the condensor failed. A Boyer Bransen unit resolves this for good and all.

If it was none of these then I wonder about fuel starvation or a failing petrol pump. Number one culprit is a blocked filter - particularly those glass and chrome ones. They look clear but are actually blocked with micro particles. Blow through them to test. Take the cover off the pump (two little screws) and check the chambers aren't blocked and that the diaphram is in good order. Check that the pulse out of the pump are strong - you pull the pipe off the outlet and turn it over. The petrol jet should jump a couple of inches at least (can't remember the exact height but someone will correct me, I'm sure).

There's a little filter on the inlet to the Solex (there's a 13 or 14mm bolt head on the boss next to the inlet pipe that you unscrew and it is behind that). Check that and clean it.

The other possibility lies in the float chamber. Is the float sticking maybe? Take the lid off and check that. Check the float height while you're there.

Might also be worth pulling the fuel pipe off the tank and just blowing through to check resistance. Have a look also at whether any breather hole in the fuel cap is clear.

These things are notoriously difficult to track down and inevitably something really simple. You have to work your way through it. Remember that it needs fuel, spark and air...

[Ken Hanna]

Highwaylass,
if replacing the condensor hasn't improved matters, I'd agree with Geoff that it sounds like a fuel delivery problem.
Have you checked that the short section of rubber hose which connects the nylon pipe to the tank pickup/sender unit is on good condition?
That's a favourite on standard A series cars, especially if the rubber section hasn't been replaced since the day the car left the factory, despite having had a chassis change in the intervening period.
It's also more likely to manifest itself on long uphill sections, where the pump has to work harder to lift more fuel from the tank to the carburettor.
One way to check that was to tackle a long hill at full throttle and stop as soon as the engine begins to misfire, whereupon removing the carburettor lid would reveal a distinct shortage of fuel on the bowl(s)...

[Highwaylass]

I think it was a combination of being a numpty and also that what should have been an increase in jet sized proved to be a decrease as the original has been drilled out.

If anyone would like to learn from my mistakes:-

- points box on too tight, restricting the advance

- 125 jet proved to be a step down, not a step up! Flat spot when changing into second

- kangaroo problem resolved with new points and condenser. Wish I'd had a set in the car, would have saved my weekend!

- fuel filter very dirty, swopped for new one and new length of hose.

[Geoff Ryall-Harvey]

Try a Boyer Brandsen transistor ignition. The condensers that we get these days are not up to much. It will also vastly extend the life of the points.