Sudden loss of power when engine warm

[Rickety]

1963 Morris, 1098 engine.
I've tried to explain the problem as fully as possible. Also to say what I've done thus far....

On turning on ignition petrol pump ticks away until full. Starts ok with choke. Runs ok and can steadily reduce amount of choke. Runs normally in all gears for about 10 - 15 minutes. Then problems start. Sudden loss of power. Engine will keep going if I am very gentle on accelerator. Putting my further down and its liklely to stall (then hard to start). If pull in on problem starting engine will idle fine; all cylinders operating ok. Will accept throttle and can rev as long as you like. But if start to drive again have to limp along with minimum acceleration just to keep engine alive. Left for 30 minutes plus and its back to square one; all ok and running fine.

What I've done: new plugs, points and condenser but nothing else.

Would much apprecaiate a sort of checklist of things to try . Ie try this first , then try .... etc

Most grateful for any help.

In driving a moggie for nearly 40 years I've never experienced this problem

Rick.

[tomothy94]

could it be a leak in the fuel line that only occurs due to the vibrations of the car moving? or else, the fuel pump may be getting stuck as heat causes things to expand..

[bmcecosse]

Sounds like fuel starvation - I would try a flow test on the fuel pump - pump a gallon of petrol into a can (not in kitchen and not smoking fag...) and tell us how long it takes.........

[Rickety]

Ok thanks - seems like fuel might be the culprit. Will investigate further - if it ever stops raining.

Rick

[kennatt]

Its easy to check,just drive it and when the problem crops up just switch off and coast to a stop,then take the top off the carb and see if theres enough petrol it the bowl,if its full then the problem lies elswhere,if not then pump,float needle valve,or line obstruction

[Rickety]

Thanks for various suggestions etc.
Another frustrating day. Concentrated on fuel. But as far as I can tell nothing wrong with supply either from pump or carb. Float chamber 'normal' level when cap removed post 'problem'.
It's very predictable. I've worked out that it goes about four miles before problem starts. Today it felt more like one or more cylinders wern't firing properly but again will rev ok when out of gear....and crawls along ok in first gear.
After incident today would not re-start until fully cooled down.
Where next ?

[bmcecosse]

If you are SURE it's not fuel (the important point in the test above was to switch OFF and coast to a halt..) . Condenser may be failing when it gets hot - try another one.

[fussyoldfart]

I would also check that the carburetor and inlet manifold gaskets are not leaking causing a very lean mixture. Have you tried a notch or two of choke when it lacks power?

[Rickety]

The latest...

Have thoroughly cleaned carburetor and float chamber.

Won't start at all now ! Convinced no fuel is reaching plugs. After several turns removing a plug would normally reveal a flooded plug. But it's dry as a bone.

What can be wrong with carb ? What test can I do to isolate carb as culprit ?

Thanks for any suggestions

[bmcecosse]

Pour an egg cup of fuel down the carb throat and crank it...........

[MarkyB]

Did you check that the pipe leading to the jet is clear?
Silt can find it's way in there and block it.

[v c bhatia]

Sir

Same problem with my morris minor 1952 split glass
Please suggest me what you have done
I checked everything
Coil is ok
Condenser also replace
Spark plug also replace
Distributor cap also checked
Point also perfect
Cables of spark plug and coil also replace
Carburettor also cleaned all fuel pipe ok
Fuel pump flow is also ok
Roter arm is ok

What else to check to know the reason of dropping of current after running for 1/2 km
Once engine cool down again it will start

Please suggest what could be problem
My mail I’d vcb.1955@hotmail.com
I am using this car since 1952 never face such problem

Regards
V C Bhatia
Mumbai India

[myoldjalopy]

Assuming you have tried all the suggestions made in this post, I would question if the coil and rotor arm really are OK (I have known rotors to look good but periodically fail). If you can, try a new rotor arm and a good known coil. It might be worth trying a different condensor as some modern ones are poor quality. But do these one at a time so you can determine which one was the culprit.