Morris Minor Owners Club

Hello All.
I am at my wits end trying to find the problem with my 1961 pickup.
The problem is that the pickup has a 1098cc engine I think?. and I can drive it any distance, but if I park up for about 20 minutes
the petrol pump don't work, if I pull the choke out it starts an runs but is missing for quit a while then picks up and away we go.
If I park up for an hour the petrol pump works ok, it also works if parked overnight.
I have put a reconditioned petrol pump on but it will not stop pumping, I also tried a s/h pump, that also won't stop pumping either. Last night I drove it slowly round the lanes for about 4 miles, it then stops, the petrol pump is not working, I took the
carb top off, it was dry, I filled it up with petrol put it back together, it went untill the bowl was empty, I done the same again, started it
up and the petrol pump worked again.
Today it started I drove it 15 miles parked up for 45 minutes, it started ok and I drove it back home 15 miles with no problems.
Any sugestions.
LRV745.

Oh dear! Loose wiring connections? I would rig a wire direct from the battery to the pump to see if that makes a difference. It's really odd that it 'stops' - when that happens - have you tested for a vacuum in the tank? Take the filler cap off - is there a sucking noise - and does the pump start ticking? Other possibility is some junk in the tank - periodically obstructing the inlet ...

Thanks for your reply, I have had the petrol tank out, there was some rust in it, I cleaned it out and put the air line through the tank outlet and blew it through, and also the pipe through to the pump end with it disconected.
I will try the cap but I have replaced it with a locking cap. I will try a wire direct from the battery.
LRV745.

Locking caps are sometimes not vented!

When you say at some times it doesn't stop pumping, I assume its pumping air not fuel? Does it run better with a full tank of petrol than say half or quarter? Could be a fuel pick up problem in the tank...

No I said if I fit a reconditioned petrol pump or a good S/H one they don't stop pumping, but if I put the original one back on it works as normal, until I go for any distance and park up for about 20/30 minutes, then the pump don't work, it will start if I pull the choke out, it misfires for a while then picks up and goes as normal.
With regard to the locking fuel cap, the same thing happens with the original cap on.

How do you KNOW the 'pump don't work'....and why do you think pulling the 'choke' helps that? This is getting confusing.......