High Idle

[blue_cortina]

Hi Everyone. Well I seem to have got past the starting issue on the Moggie and even managed to start it on the handle when it had only sat a couple of days. I've got the points set to give 58Deg dwell angle. I've used a vacuum gauge on the inlet manifold and it's giving a respectable 20ish InsHg.

The issue that I have is that it is ticking over at over 1000 rpm on idle. The idle adjust screw isn't even touching the cam it operates so I can't reduce revs by using that. I believe the choke mechanism is also fully off.

I have weakened the carb mixture a little by winding mixture nut up, and that is now several flats above the two full turns baseline. Maybe it needs further weakening?

I've also checked and as far as I can see I'm getting no additional air leakage into the manifold.

What can I do to reduce the idle to something more acceptable? Weaken the mixture more? Retard the timing ?
Any help would be appreciated - we are so close to being able to use the car...

[myoldjalopy]

Is the accelerator cable too tight? Maybe try slackening it a bit at the throttle linkage....or the throttle return spring not set properly?

[blue_cortina]

Is the accelerator cable too tight? Maybe try slackening it a bit at the throttle linkage....or the throttle return spring not set properly?

I think I've checked this but I will go out and check it later when the heat has reduced - i've been out there for half an hour and I was melting!

[blue_cortina]

Spent a few hours on the car yesterday and with the help of a good friend managed to get to the root cause of the issue. When I rebuilt the carb the New flap that I fitted didn't seat right and was letting in too much air. Long story short we refitted the old flap which (after years of wear) seated much better and closed the air off. With it closing right we then make it open as much as we wanted with the idle control screw. The idle speed is now set just high enough for the dynamo/ignition light to just go off and the engine sounds much happier.

We are now a big step closer to road use !!!