Hi all,

 

My bready (1043cc) has been running fine for quite a while until lately after about a 20 - 30 min drive it starts losing power at around 50+ mph. Most recently after getting up to about 60-65 mph on a dual carriageway it really started struggling and eventually I lost all power completely with the car lurching to a stop - almost like the wider I opened the throttle the worse it got.

 

Managed to get to a lay-by just before it cut out and it wouldn't start again. Until of course recovery arrived when it started OK! If I recall the battery light came on before it died but I can't be sure of that. So it could be alternator or belt / tension. But the battery seemed OK and recovery chap seemed to think it was charging OK. I drove home fine and the car was idling OK but I was keeping to about 50 mph max.

 

I think I'm going to pull the plugs as I did have an issue with rich running a while back and it might tell me something. I'll also check the fuel filter, jets and alternator belt / tension. Most of the ignition bits are pretty new. At the back of my mind I wonder - could it have been carb icing (it was probably about 6-7 degrees outside)? I've not experienced this before but I don't drive it much in the winter and maybe the temperature valve thing is not working? If so is there any way to test?

Sounds a lot like carb icing to me. 

If there is a thermostatically controlled blend flap try wedging it in the fully hot (maximum pre-warmed air) position and see if symptoms desist.  Check any convoluted hose that feeds this pre-warmed air in, if such exists.

Edited 10 March, 20233 yr by Pete1

Yep, carb icing seems possible, or fuel starvation?

 

Icing in my experience, usually starts with a slight hesitation and gradually gets worse until you grind to a halt as the ice develops on the carb Venturi and over chokes the engine. Once you stop, the heat from the engine melts the ice and bingo, off you go again 10 minutes later. It then goes through a repeat cycle…ok to start with then the gradual loss of power starts again. Speed seems to be a key ingredient, the faster you go the more likely it is to occur.

 

For  Icing and as Pete says, if on a standard setup check your warm air flap in the air cleaner nozzle is not stuck shut. What year is your Bready? If it’s got a 1B3 or 32TLA carb It opens via a vacuum system with a pipe from the carb to the air cleaner, then another one to the warm air flap in the air cleaner nozzle. Also ,make sure your flexi pipe from the exhaust manifold is present and not split or hanging off.

 

In cold ambient temperatures and with the engine cold you can pull the thin vacuum pipe of the diaphragm on the air cleaner nozzle you should be able put your finger over the end of it and feel a slight suction from the vacuum. The axis of the flap can be seen on the wing side, I painted a thin line/spot on mine, so you could see the flap move into it’s closed or open position. 
 

Failing  that, unclip the nozzle from the air cleaner and you can look down it to clearly see the flap either open or closed across the inlet from the manifold.

 

The colour of the plugs is a good clue though, black and it’s over fuelling or poor air flow/misfire.Icing causes the AFR to be disrupted, so you will probably get blackened plugs with that, 

 

Fuel Starvation is another problem to consider also water in the fuel. Condensation can be an issue at this time of year, especially if you run with a tank never full.This happened to me once with water in the vaporiser, but in that case my engine would idle but no power, as the water was in the bottom of the carb being sucked up the main jet, but seemingly avoiding the idling jet!

Edited 10 March, 20233 yr by mk2tastic

id go with carb icing too....doesnt have to be icey weather to cause it 

or rusty sludge in fuel line (check fuel filter, replace, blow back into tank with air) that sinks back down

 

or if has Hall sensor that might be dying when hot, but for me I got backfires before cut

 

Battery light is interesting. Also check the alternator plug has not wiggled loose and for 14.2 or more volts at battery when idling. Need strong sparks at higher revs.