Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Morgan Misfire and lumpy running under load

Hi folks,

Sadly, drive-it day ended for me and my Mog with a trip home by breakdown truck.

The day started well and all was fine until the Mog was nicely warmed-up, after about 10 miles, it then started to run lumpily before cutting out. It will start and tick-over but cuts out under load. It seems better now it's cooled down.

My Morgan is a bog standard 4/4 from 1972 running the Ford Kent engine with no mods except an unleaded head.

One thing that has occurred to me is that immeditely before the issues I had just filled it up with Tesco 99 octane Momentum petrol, which I have not used before.

Any ideas?

Cheers

Nigel

That sounds like too much of a coincidence to not be related to the fuel somehow.

I'd certainly pump it out and try some other fuel as a first port of call.

Good luck.

Try the petrol option first...coincidence seems a possibility.
If not sorted check the age of your plug leads. I once had similar on a car and new leads sorted it. Car ran ok until warm then lumpy when under load. Not expensive ones either as I was about to sell the car.
Remember....many systems on Morgans deteriotate with age, electrics, rubber hoses etc..

Those symptoms sound like a coil breaking down..but if you'd just filled up, then that's where I'd be looking first..

I'd suspect the condensor/capacitor in the distributor,

Sounds like the condenser to me, unfortunately lots of modern ones are poorly made and fail when hot

You could try using fresh fuel from a can to save draining the tank?
It could be plugs, points, leads, coil, distributer etc If it is good luck. On the old Kent engine first thing I usually did was take a plug out and check the spark then may be a colour tune.

At least there is no ecu or maf etc to look at.

I would suspect cr*p fuel too! If all else fails try the ballast resistor. My ‘69 used to eat them regularly.

What a coincidence, the same thing happened to a friend today on our drive it day. same symptoms, same end, the AA truck. Consensus seemed to be a fouled carb as two plugs were black and two were clear.

I agree. If it was fuel, there would be an awful lot of stranded cars in the area!
IMO, Condenser is most likely, but coil and ballast resistor and HT leads are other possible candidatrs. As a general principle, always best to start with cheapest, easiest solution and in this case that has to be condensor.