General Franko the 1971 500L

[Franko500]

Ignore that statement. It looked like I was on max idle adjustment but in reality it's 1.5 turns on the idle and 3 turns out on the mixture.
The fuel filter was empty when it stalled. After a few minutes turned off it was full again. Started straight away and I have just notched the tick over up slightly. Fingers crossed[emoji106]

 

[the hobbler]

It is not unusual to have a slight flat-spot on initial acceleration, particularly if you just wack the throttle open---the basic 26 (and 28) carbs have no accelerator pump. Initially therefore (albeit very briefly) the mixture is very lean.

 

[Hobo1960]

Could it be vapour lock as it it appears to happen when the engine has been idling for a long time? This could explain why the fuel filter is empty and then fills up again after the engine's been switched off and cooled down for a few minutes. A petrol pump will pump liquid, but not a gas. Has the pump got the correct insulator installed? If it's a replacement part is it made from the correct material?

I don't think the timings the problem, although too much advance will cause an engine to run hotter and increase the risk of vapour lock.

Howard

 

[Franko500]

Well I swapped the idle jet over & I took him out for a long run. He drove really well and didn't falter once.
Even at junctions there was no sign of stalling which had occurred before.
I also stopped outside a friends house to view his MG M-type (I thought I had problems) which has the engine in parts and he doesn't know what to do? I left Franko running and still no problems. I'm wondering if I had the tick over too low before? It's a little faster now and I don't have any issues selecting 1st or reverse which is always a tell tale sign the idle is too fast.
So for now I will just wait to see if its an intermittent problem.
Regards the pump insulator block, its an original one which has very clean & flat faces, new gaskets and nuts are done up tight.
I might take it off soon and check the distance that the shaft sticks out. My theory could be that on tick over it may not be pumping enough fuel if its not getting its full stroke. And yet at higher revs the pump is working quicker and therefore pumping more fuel to the carb.

 

[Hobo1960]

Well, fingers crossed, it sounds promising.

I blame modern petrol, it has a short shelf life and destroys some of the metals used in classic carburetors.i'm always surprised by the crud that I find in my float chambers and that's after the petrol has been through three filters!

All the best
Howard