Triumph Repair: Rough idle when starting warm, spitfire 1500s, float bowl

Question
I have a 1980 Spitfire is a good running car. The only issue that I have had since the day I purchased it 4 years ago is that after running for a while and shutting it off it runs rough and won't idle for a while after restarting. I have heard it is the gas boiling out of the carb. Also, is it normal that the engine doesn't drop to idle very quickly? My EGR valve is likely caput as I can't see it working when applying vacuum to the port located on top of the valve.

Answer
Frank,

The late Spitfire 1500s were 7.5:1 compression in stock form and the carbs were set to avoid a quick drop to idle to minimize NO formation.

Having said that, it's also possible that after 30 years the linkages are a bit gummed up.  

If the fuel pump is working properly it should fill the float bowl within a minute or so of starting.   Hard starting would be more of a symptom of the fuel boiling off.

I've never driven a Spitfire with an EGR valve, they're missing or the exhaust has been swapped for a header without EGR, so that may also be part of it.



Cheers,

Jim