Rough idling on 1967 Minor

[Maurice_Minor]

I had my Moggie laid up for a month because of the weather & I went to start it today (With its new 60 AH battery & eventually it started but sounded very rough. I let it warm up, but the idle is still rough & it constantly wants to die. The last time I drove it, the car ran like clockwork the last time I drove it. All the spark plugs are dry & the correct colour & there is nothing else obviously amiss.
Any ideas will be appreciated.

[King Kenny]

Could be damp in the distributer.

[James k]

Check that the choke isn't stuck on.

[myoldjalopy]

Damp in the dizzy is definately a possible cause, especially this time of year. Are you running on points or electronic ignition? If you have points a failing condensor will cause rough running and cause the points to start burning out. Are you getting a good spark at the king lead?

[JOWETTJAVELIN]

Battery connected the right way?

[paul 300358]

E10 petrol?

[Maurice_Minor]

Thanks for all the hints as to what might be the problem. I have gone through everything as suggested & all seems in order. The one thing I did notice was the breather pipe from the engine to the carb was very hard & I was able to just pull it off at the carb end, the pipe was so distorted I couldn't even tighten the ancient jubilee clip. Presumably air must have been getting in, whether this is the problem I don't know, but I have ordered another pipe. Oddly the pipe was also travelling just above the exhaust manifold, which might explain why the rubber was so hard.

[paul 300358]

E10 petrol? Gummed up jet? I would be tempted to take it for a good run and then see how it goes.

[svenedin]

It could be fuel related (fuel starvation). I have just had a similar issue with my fuel pump. Is it a points type fuel pump? They don’t like sitting around. Contacts get an oxide film.

[Maurice_Minor]

It could be fuel related (fuel starvation). I have just had a similar issue with my fuel pump. Is it a points type fuel pump? They don’t like sitting around. Contacts get an oxide film.

It one point the car started & it over revved regardless of the position of the choke. It was roaring away until I cut the engine, then it started again & back to sounding & feeling lumpy..
How did you establish the problem was your fuel pump?

[myoldjalopy]

That sounds like a sticky accelerator cable or throttle linkage.......

[Maurice_Minor]

That sounds like a sticky accelerator cable or throttle linkage.......

Yes it does sound like that, but it wasn't.

[James k]

You can check the fuel pump by disconnecting the fuel line from the carburettor and switching on the ignition, collecting the fuel in a container. If it's delivering a good flow of fuel, you can rule that problem out.

You say the position of the choke made no difference. Are you sure it's not stuck at the carburettor end?

[svenedin]

It could be fuel related (fuel starvation). I have just had a similar issue with my fuel pump. Is it a points type fuel pump? They don’t like sitting around. Contacts get an oxide film.

It one point the car started & it over revved regardless of the position of the choke. It was roaring away until I cut the engine, then it started again & back to sounding & feeling lumpy..
How did you establish the problem was your fuel pump?

Didn't know your car revved too high at one point. As already suggested you can test the fuel pump by disconnecting the fuel hose at the carburettor and putting the hose in a container and then turning on the ignition. It should pump away happily. Of course take all precautions with petrol. My pump had an intermittent fault and so the only way I could ascertain it was not working properly was to wait for the car to stall and take the lid off the float chamber. There was no fuel in the float chamber and rusty debris too. Your over-revving doesn't sound fuel pump related but lumpy idling as if it was about to cut out could have been. What else could cause it to over-rev other than the throttle stuck open?

[myoldjalopy]

That sounds like a sticky accelerator cable or throttle linkage.......

Yes it does sound like that, but it wasn't.

Well, I'm sure you would have noticed, but is the throttle return spring present/damaged/fitted correctly?

[Maurice_Minor]

That sounds like a sticky accelerator cable or throttle linkage.......

Yes it does sound like that, but it wasn't.

Well, I'm sure you would have noticed, but is the throttle return spring present/damaged/fitted correctly?

The mystery is up till the car was placed in a dry garage, the engine ticked over like a fine watch & then 4 weeks later (After the frozen spell) I tried starting it & although there was a new battery in the car, it still took an unusually long time to start, when it did it was lumpy & failed to idle.
It does seem like a fuel issue. I do put E5 in it. I noticed the distributer is new & the inside spotless.
It is a puzzle that would tax the brain of even the great Poirot (If he was a mechanic)

[svenedin]

Sticky float valve could also explain rough idle and sounds like it’s going to cut out. Doesn’t explain the over-revving which sounds like a separate issue.

[Maurice_Minor]

Sticky float valve could also explain rough idle and sounds like it’s going to cut out. Doesn’t explain the over-revving which sounds like a separate issue.

I think the float valve sticking sounds plausible.

[Maurice_Minor]

It could be fuel related (fuel starvation). I have just had a similar issue with my fuel pump. Is it a points type fuel pump? They don’t like sitting around. Contacts get an oxide film.

Your theory would explain why in spite of a massive 60Ah battery being fitted, the Moggie took ages to start in spite of the motor being spun around, I put it down to the cold spell, but now fuel starvation sounds like a more plausible explanation. I think I'l explore this option.

[Myrtles Man]

You could check if it's fuel starvation that's the problem by giving it a squirt of 'Easystart' up its trumpet before trying to start it. If it fires up immediately, as it should, then falters and/or cuts out, then there's your answer.