Unable to adjust tickover

[Billancourt]

Hi All

I have an R4gtl with a Zenith 281f carburettor. The rpm is ticking over at 740 rpm which is ok. However, if I screw the idle screw in or out, nothing happens. No increase or decrease in rpm. Any pearls of wisdom as to why this might be would be gratefully received.

Best Wishes

 

[malcolm]

The screw on the side of the carb is to control the mixture at idle. About 1.5 to 2 turns out from fully in is a good starting point.

The idle speed is adjusted by another screw that acts on a stop for the cam where the throttle cable attaches.

 

[Billancourt]

Hi Malcolm

Thank you for your reply. It is the idle speed I have tried to adjust on the stop for the cam by the accelerator cable but there is no increase or decrease in rpm when I do so.

 

[André4Renaults]

It's possible the idle cam is sticking, so that the adjuster's not working. Try screwing the idle screw in a few turns and then flick the throttle linkage and see if the revs settle at the same level. Remember that the engine will take a few seconds or so to change idle speed once you've altered the setting. How much are you adjusting the screw by each time?

 

[Grenuj]

However, if I screw the idle screw in or out, nothing happens

it will happen when you pull this bar up:

 

[Billancourt]

Hi Malcolm, Andrew and Grenuj

Your combined knowledge helped me resolve the issue.

Many Thanks