Tickover Spitfire 1500

[Bren]

My 1500 starts and runs great. Idles at around 850 rpm when off the choke. However when the engine gets warmed up, the idle rises to 1000 rpm. If you blip the throttle it drops back to 850 rpm, but then solely rises to 1000.

Any ideals? I have checked for air leaks as (much as you can) including the vacuum tube. 

[Pete Lewis]

sound like you need some slack in the throttle cable as it warms the cable pulls the idle up

Pete

[Bren]

Thanks Pete, I will give that a go, it could well be something as simple as that!  

[Pete Lewis]

if the simple cable doesnt fix it you are likely to have throttle plates fitted with the nasty poppet valves 

if the spring fails you get a racing idle but if there is need for a clean it can upset  normal idle 

do mae sure no air cleaner gaskets are obstructing the carb front face

Pete