MGB Intermittent rough running / lack of fuel ? Help

[retroracing]

So got my project mgb running fine the otherweek after checking the timing, and stripping down and cleaning out the carbs. Tuned it up and took it for its mot.

Was running spot on. Got to Sainsburys, turned it off to get some cash out, got back in and was running super rough, misfiring and would barely pull, so I stopped in a layby.

Managed to limp it home, took 2 hours to do about 5 miles stop starting!

Sounds like its running out of fuel but it had £20 in it.

Checked fuel pump. Pumps 2 pints in about 45 seconds so thats ok.

So swapped the leads, cap and rotor arm for the ones on my mini I know are good, changed the plugs,and tore the carbs down....again.

Found front float to be catching on the side of the bowl, think it was misshapen due to age.

Fitted a new float today, and it was spot on, problem solved!

Tuned it up and was running sweet. But then started to miss very very slightly at high revs, so I went and got some more fuel as sounded like it might be low.

Stuck some fuel in, now it will barely start again and running super lumpy!!!

Could the fuel pump be working intermittently??

I'm all out of ideas, so and help is much appreciated,

thanks Retro.

[Steve_D]

Check the condition of your fuel hoses. Have seen (more than once) where the inner skin of the older fabrc and rubber hoses has become detatched so a flap can block the pipe.
Long shot I know but it may be there on an older car.

Steve

[Mr2Mike]

The original SU electric fuel pumps are infamous for their unreliability so this would certainly be a suspect.

[NTEL]

I had similar symptoms on my 5L RV8. Kept blaming fuel and carbs but I eventually traced it back to the lumenition ignition system. Replaced it with an MSD ignition and all is now good. Are you using points or electronic ignition?

[jagracer]

It could be sucking crap into the carbs. What ignition are you using? Is it an 1800 or V8 engine?

Edited by jagracer on Friday 11th May 20:39

[davepoth]

Next time it's running rough, find out how hot the coil is. I suspect it will be very, very hot, because it's broken down.