Cold Start problems - Very odd!

Hi Just wondering if anyone has an idea of why my car takes longer to start when cold. I have a 1987 Rover 216, it is a carburretor type engine (not the later efi engine). If it hasnt been run for about 4 hours or more, it takes about 10 seconds of cranking to start, then it is fine. If you turn it off and on again, it will start up instantly! After being started once, it will start up instantly again if left for up to about 4-5 hours. Anything over this and it will again take about 10 seconds of cranking to start!
The engine then runs perfectly, it has new sparks & leads - no problems with the ignition system! The only odd things are... Upon turning the key, the fuel pump makes no noise, only when cranking the engine, Someone has fitted a magnetic fuel saver device in the fuel line at some point.
Could it be a faulty non-return valve on the fuel pump??
Any suggesttions would be appreciated! Thnks!!

 

[TheBlacksmith]

The Faulty non-return valve sounds possible to me. Could be a leak in the carb. Something is letting the carb drain down slowly so there is no fuel for the first start.

Blacksmith

 

[sprintcar]

Rochester QJ carbs and others use plugs in some of the drilled passages to block them off at the base. Over time moisture can rust these out and allow the bowl to drain slowly.
Fuel pump valve is also likely. You can probably check that one by taking the line off the carb (engine off) and hang the open end up in the air.... check the level in an hour.

Or maybe the magnetic fuel saver is busy aligning all the gasoline molecules while the engine is off and now they're stuck inside the fuel line......... Keep the wheels on the ground
Bob
showshine@aol.com

 

[sbc]

It could likely be the fuel pump relay if the pump only
runs after cranking. 'Sounds like when you get oil presure
you get fuel.