Revving on start up

[Garth]

Can anyone shed any light as to why my RRC revs to about 2500 RPM for a couple of seconds when I start it.  Its only done this since I replaced the advance\retard diaphragm so it would lead to that.  Are there different types and how do you tell difference

[Range Rover Blues]

I'm assuming it's a 3.9 hotwire then if it's a '91.

There are one or two things it could be

Idle stepper sticky or faulty
base idle set wrong
timing well out or sticky
leaky injector/overfueling

does it need a lot of cranking?

[Garth]

Hi

Cheers

Yes its a hotwire

Timing is set to as far advanced as possible on petrol without pinking
Advance retard works ok altho tube is a bit ropey
Starts on first couple of turns and ticks over at 700 ish when calmed down

I will look in manual and check stepper thingy

[jpc]

mine does the same i presumed that it was the automatic choke? :oops:

[Garth]

Took Air bypass valve (stepper thingy) out tonight cleaned up and checked it was working and it is.  So its not that. :(

[Garth]

May have spoke too soon

Last two mornings and nights seems to be a bit better so I will take out again and give a good soak of WD40.
May be working but be a bit sticky!!