Talk Morgan Forums Community The Malvern Arms Interesting experience in the Morgan yesterday.

Hi guys, long time no post!
Heading down to the big smoke ( Melbourne ) from country Victoria early in the morning, cold and damp despite being early Spring here.
Had been going for about an hour averaging 100 - 110Kph when there was a vague change in the note of both the air intake and the exhaust. Over the next few kilometres the change in sound intensified and there was a noticeable loss of power. Luckily came to an off ramp from the freeway, changing down through the gears as I lost more and more power until the engine died 😱

I had visions of the Mog going home on the back of a truck but first I did what everyone does in this situation………
Swore, got out, lifted the bonnet and tried to give the appearance of someone who knows what they’re doing🤣
Checked the usual obvious things, plug leads, distributor, fuel filter and then I noticed there was condensation all over the inlet manifold and carb ( Twin choke side draught Weber ).
While drying it all off with a rag I had a 💡moment…….started her up and after a bit of coughing and spluttering, all back to normal.
I was aware of the phenomenon but never experienced it in over 50 years of driving.

Kind regards to all.
Neil.

Sounds like the carb was icing up caused by the cold and also the intake of fuel, this is further confirmed by the condensation on your intake manifold. Later in the hotter weather the car will go to the other extreme where you may have vaporlock where the fuel lines and carbs get to hot and again cause fueling problems due to the fuel turning to vapour in the fuel lines/carb.

So for now get some more heat into the carb area, ie reduce the cold airflow to the intake area ?

A weaker mixture due to the icing will cause bad fueling and resulting backfires noise in exhaust also.

Yes carb icing was my first thought and reducing engine power makes it worse given higher manifold depression. Carburated piston aircraft engines have a carb heat control use of which is part of pre-landing checks to offset icing when engine power is reduced.

I've only ever had this happen on a Gilbern Invader on cold mornings at motorway speeds. A gradual but significant loss of power. I found that as the speed dropped away it cleared until the next time! The carb was located high up in the Vee with no warm air feed.

The joys of driving old cars Neil but it's good to hear you are safe and back on the road.....

My first car (an Austin A40) .... had an air cleaner with a Summer/Winter position .... Summer the air cleaner intake pointed forward into the airflow .... Winter you turned it downward to pull warm air from over the exhaust manifold.

K

I can remember that, think it was on my MG Midgets.

They'd both be A-series engines of the same period .... simple manual and foolproof ... nowadays there'd be solenoid operated flaps worked from the ECU taking GPS co-ordinates and live updates from a weather satellite .... and cost £2K to repair when it went wrong! 😄

K

In my youth, the smaller and cheaper cars, at least some of them, had just such a lever to divert to warm or cold air, e.g. my Renault 6 MY 1975. More expensive cars sometimes had some kind of bimetallic switch instead of the manual mode to channel the airflow. So the drivers of these more expensive cars knew less about carburettor icing and remained dumber in technical matters.

Ditto experience with a Gilbern Invader Mk2 Estate. Can't be many ex-Gilbern drivers on here.