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After replacing all the vent pipes & both steel fuel lines I had the car running nicely. However, after an extended layup whilst I changed the front shocks I find it won't start.

It seems like I'm not getting any fuel through to the carb. (Yes, the tanks are half full).

What is the fuel route?

I have a line from the tank through a glass bowl filter (may not be standard) which has an arrow pointing towards the (Weber) carb. Just below the inlet on the carb there's an outlet through a (charcoal?) canister to the fuel pump. Pump filter is clear but it's bone dry - no sign of any fuel. From the pump a line goes backto the tank.

So, I assume the fuel pump sucks fuel from the tank up through the filter to the carb & through the canister then spits the excess back to the tank.

There seems to be some fuel in the return line but nothing coming inbound. I've blown back through the inbound line & it's clear into the tank. Is it an airlock?

It's always taken a while to re-prime after a period of not running but not even 30 seconds of turning over has any effect.

I've heard about airlocks with these mechanical fuel pumps indeed.

I meant to post an update on this.

I disconnected the pipe from the inline filter & poured petrol down into the carb until the pipe started to overflow. I reconnected the pipe & got it running.

I haven't had any problems since although if I don't run the car for a couple of weeks it does take a little bit of spinning over to fire up. I does indeed look like it was an airlock in the pipe.

Good thing it's solved then, and it wasn't too much work. Usually it only takes lots of time to figure out!