Low idle speed

[Sir Paolo]

Gents, some advice/suggestions please. My engine is about 2k miles old since a full rebuild and recently I've noticed the idle speed dropping. It is a 2.2 n/a running on L14's so it idles happiest at around 1200rpm.

However it now drops to about 1k rpm, and seems like it is going to drop further/stall but this is steady although it's a bit unsteady.

I haven't started investigating yet other than checking for loose leads etc, so would appreciate any pointers. I'm thinking maybe ignition timing but can't see why this would change.

Many thanks

Gents, sorry should've added, I've adjusted the idle speed at the carbs to about 1200rpm, but after a couple of minutes it drops to 1k again

[mdw]

I know on my 88 2.2n/a once its most of the way throught the warming up period there is a noticeable drop in idle rpm when ( I think ) the throttle jack solenoiod ( near alternator) drops out as it warms up. Mine is 1k on a rebuilt stage one engine so probably different cams. Might be worth a read through the service manual as it it explains the whole emissions kit process operation quite well and you can fault find it from there.

Once fully warm it ticks over at 900 rpm and is happy at that.

[Sir Paolo]

Thanks Gents.

Scott, the normal idle is high, but this was set by the dyno operator to compensate for the valve overlap of the cams.

In normal circumstances, it's happy at 1200rpm.

[Sir Paolo]

Thanks Gents.

Scott, the normal idle is high, but this was set by the dyno operator to compensate for the valve overlap of the cams.

In normal circumstances, it's happy at 1200rpm.

[Sir Paolo]

By way of an update, all plugs are a fairly uniform colour - if a little on the rich side.

So it'll be a timing check next ......

[Sir Paolo]

Dear all, I think I may have found the problem. Inside the (new) distributor cap there were oily deposits, and some of which has made their way onto the rotor arm tip and points inside the cap and burning.

A quick clean of all the points and the difference was immediately obvious!

This collection of oil in the cap is probably a result of the dizzy lying on its side.....

[mdw]

New rubber o ring time?

[Sir Paolo]

Malcolm, you could well be right, but I had the dizzy fully rebuilt (by Aldon) while my engine was in bits.

I think I may have over oiled the felt pad under the rotor arm