SU H6 needing slow running adjustment.

[Richardtr3a]

After a short run today the carbs need some adjustment, The engine starts on the choke and runs well. But as you slow down at traffic lights or a junction the engine dies. I can keep it going by blipping the throttle. After it has stopped it starts immediately on the key and runs well.

 

Something needs cleaning/unblocking. Please advise.

 

Thanks Richard & H.

[Fireman049]

Hi Richard ~

 

Could it possibly be caused by a vapour lock?

 

Tom.

[RogerH]

HI Richard,

assuming that the carbs are in reasonable condition then the only slow running adjustment are the screws opening the butterflies slightly

screw #17 x 2 http://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/fuel-system-induction-controls/carburettors-manifolds/carburettors-air-cleaners-h4-su.html

 

The ignition timing will affect the slow running.

Air leaks at the manifold will affect slow running .

As will a worn butterfly spindle.

 

If the engine ticks over OK under normal conditions but stops when slowing down (ie reducing throttle position) then there may be something more than a simple adjustment of the above screw.

 

Roger

 

PS - it could be that a sudden throttle closure brings the tickover to the correct level but is too low.

The setting under normal conditions may be affected by a stiffness in the butterflie spindle - not closing fully.

Edited December 5, 2016 by RogerH