The V8 Owners Forum -

MOT yesterday, passed first time!!

Putting some running-in miles I have done about 150miles: going great until a nasty problem arose on the M25, not far from home.

The engine was a bit rough for a while then just coughed and stopped. After a short while it started again, went for a few hundred yards then coughed and stopped again. This happened several times, and I finally called Green Flag. By the time they arrived I had the engine ticking over and they followed me home.

Seems like a fuel problem, perhaps? Airlock of some kind, perhaps? It hasn't been very hot today, and she was running on the motorway at a reasonable indicate 90+ temperature .

I just drove 2 miles to the village for fish, chips and beer with no problems.

I would appreciate any thoughts. Do I recall something about a non-return valve on the fuel system or am I thinking of my central heating?

Roger

Roger
This is a longshot but something to check anyway. I have the same engine and carb. the symptoms are exactly what I experienced. Sometimes normally when cruising the engine would start to run rough and want to die. Then pull over and after a few mins everything fine again. It took me ages to find the problem which was carburettor iceing. Only started happening after I fitted the MGC bonnet.
Normally this time of year it is OK and tends to happen early morning or when the air is damp. To check quickly take the air filter off and you will see lots of ice built up around the primaries.
I made an alluminium shroud to block the space between the rad and bonnet which has cured the problem completeley.

worth a look.

Mark

The problem Mark describes with icing of the carb as a major problem when my MGB as road legal. As soon as I swapped my 14" air filter for the bug catcher she would ice up on the motorway if the air temp was below 20C.

Took me an age to get to the Stoneliegh show that year

As the problem went away as you describe and it was fine for short low speed runs it may be something to consider.

Get it out for another motorway blast and see what happens. If it conks again then pull over and see how much water there is laying around the carb area??
Mine used to show lots of condensation all over the carb when it conked out..

Perry

My carb ices up in the winter but it only seems to affect tickover and only for about the first 3 miles of driving.

I have had a similar stop, start breakdown with my old 3.5 engine, the fault was traced to a cheap rotor arm that was breaking down. It was purchased from Real Steel.

I've also had a coil fail, it would be fine whilst bimbling about but if I gave the car some stick the coil would pack up for about 20 seconds, the engine would then fire up again.