excessive revs with choke out when starting

[brendanmegarity]

Hello to everyone out there, I've just joined the club. Of course I've a problem to start me off. When I recently tried to start my van with the choke out the revs went sky high, this happened with a couple of more attempts. I'm new to this classic car thing and know virtually nowt bout engines other than what parts of the engine are where. I'd appreciate any help, many thanks

[bmcecosse]

Welcome to the forum! The answer is - it's meant to rev up when the choke is pulled - and you can adjust this! Either don't pull the choke (it's not really a 'choke' on the SU carb - it's a mixture enrichment device!) out so far - or under the bonnet at the carb you will see a little screw that bears on the 'choke' mechanism cam - turn this back slightly (anticlock) to reduce the revs when the knob is pulled. Note there is another screw alongside which sets the normal idle revs - don't touch that one - just the 'choke' screw. Get someone to pull/push the knob while you watch what's happening at the carb.

[brendanmegarity]

Welcome to the forum! The answer is - it's meant to rev up when the choke is pulled - and you can adjust this! Either don't pull the choke (it's not really a 'choke' on the SU carb - it's a mixture enrichment device!) out so far - or under the bonnet at the carb you will see a little screw that bears on the 'choke' mechanism cam - turn this back slightly (anticlock) to reduce the revs when the knob is pulled. Note there is another screw alongside which sets the normal idle revs - don't touch that one - just the 'choke' screw. Get someone to pull/push the knob while you watch what's happening at the carb.

thanks for the info. Can't locate that screw even with a manual. Tried with 'choke' in and the same thing, thr revs just keep goin up and the accelerator pedal seems very loose and dirty exhaust fumes comin out, would this have anythin to do with it. thanks again

[Chris Edgar]

On the carb, there is a throttle return spring which closes the throttle when you take your foot off the accelerator....check that it has not broken or just come off.
Note you said the pedal seems "loose"
If it has, this could cause the revs go go up & up out of control.

[Declan_Burns]

You can see the screws in the pics below. Also check that the large throttle return spring is intact-that can cause high revs.[frame][/frame][frame][/frame]
Regards
Declan

[Declan_Burns]

Chris-I think we both posted at the same time
Declan

[mike.perry]

Check that the accelerator cable is correctly located in the slot at the end of the accelerator pedal linkage, the outer cover is fitted into the bracket on the engine compartment bulkhead and in the cable stop near the carb.
Next to the carb as Roy said are two screws with springs around them, one might be angled downwards. The screw which tightens onto a plate against the carb is the tickover screw and as said should at this stage be left alone.
Pull the choke out as you were instructed and you will see the cam turning and the fast idle screw should be resting against it. With the choke closed the screw should be just touching the cam so that when you pull the choke out the first part of the movement speeds up the tickover to keep the engine running whilst it is warming up and further pulling will richen the fuel mixture for cold starts.

[Declan_Burns]

The other end of the throttle return spring connects to the hole in the bracket bolted on the exhaust manifold-see below:[frame][/frame]
Regards
Declan

[bmcecosse]

Your post suggested this revving up was somehow related to the use of the 'choke' - if it is not, then either stuck cable or broken return spring. The remedy is obvious......