engine idling - Stromberg

[olivier]

Hello,

I have a problem to tune the idling with stromberg carbs. The 2 idle screws at the minimum the engine is 1500 rev. Is anyone could help ?

Thanks

[oldelanman]

Check that the fast idle screws are not holding the throttles open. With the choke fully off there should be a gap between the fast idle screw and the choke lever.

Also check that the throttle cable is not sticking and that the return spring is fitted between the cable end and the airbox.

[olivier]

Check that the fast idle screws are not holding the throttles open. With the choke fully off there should be a gap between the fast idle screw and the choke lever.

Carburettor choke assemby 010(a).JPG

Also check that the throttle cable is not sticking and that the return spring is fitted between the cable end and the airbox.

the throttles are closed, the 2 screws are unscrewed. Choke is off and unwired.
I will check the stress of throttle cable.

Problem is that few miles ago I haven't got this problem. It appears suddenly.

[peterexpart]

I would check the O Rings on the Balance Tube between the Carbs, or the O Rings between the Carbs and the Manifold as it sounds more like an Air leak causing weak mixture which would increase the Tick-Over speed.

[olivier]

Thank you for your help.
I have found the problem. Simply a desynchronisation of the two throttle due to the linkage axle which was twisted. The left throttle couldn't be in the idle position, so cylinder 3 and 4 was feeded, so no correct idle. Everything is in good order now.