The 'E' Type Forum

Engine runs fine with power on, pulls hard plenty of torque delightful to drive under power. However when foot is off the accelerator and car is still in gear engine chugs and car lurges particularly at low revs. Timing is 9 deg advanced and other than this the car runs fine. Any thoughts appreciated.🤨

It’s difficult to diagnose without more info. How low revs are you talking? What speed are you going? Does it do it in all gears? What condition is your car in? Has it always done this, or is this a new thing?

When slowing down using the gears. For example when coming to an intersection using gears to slow the car. The vehicle condition is in excellent condition ( concours winner in 2011). It has always been a bit jerky at low revs after a ground up reso in 2007

Could be many things, but I’ve seen this happen when the mixture is wrong. Could be running too lean.

I'd agree with Simon......something amiss with the carbs set up.

Insufficient or incorrect oil in the dashpots causing over-rapid dropping of the piston?

Regards

Hi tight spark plug gaps cause that problem try gapping them slightly wider than they should be and see if it improves the problem

I only know one of the causes of just this kind of symptom because my neighbour told me about it. In this case it was a Ford Escort, but the cause was the same. A recently cashed up young chap who always wanted to own the car his Dad used to drive, bought one fully restored. And on his first few drives, had just this symptom. He took a mate, who 'knew about classics cars' with him on a drive.

His mate told him to shut the choke off.

Problem solved.

There's a similar story years ago about a lady complaining to the garage that her Morris Minor was running rough. The car went in and out several times but the garage couldn't detect any problem. Eventually when she came back yet again they suggested she drive one of their mechanics and see if she could point to what she meant. They both duly got in the car, she pulled out the choke ready to start the engine, and then hung her handbag on it......

All great suggestions, so here's one more: check for a stuck distributor breaker plate.

Mine 66 would start obviously misfiring and keep misfiring. Finally realized front float bowl ball bearing in the jet was sticking and front carb was starving. Pipe brushed and all well until

A month ago started running rough again, this time it was a plugged front float carb intake screen. Although it did not seem to be particles more like a varnish as I could see through the filter but fluid would not pass through. Sitting for 4 months could be a cause.

Once cleaned is much better but still has a constant misfire at all constant rpm range to 50 mph. Very smooth when accelerating. Not sure about this new symptom.

Years ago I had a misfire that was traced to the distributor, a plastic piece had failed on the points.