MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Choke ( mixture control) hard to operate

After a recent cold spell in Melbourne I thought I would tackle a nagging problem with my A. The choke has always been hard to operate - first movement (throttle advance) is okay but next movement (mixture enrichment) needs two hands on the knob and then it hardly moves. In the past on cold mornings I would lift the bonnet and pull the choke cable up by hand and start from in the engine bay.
So I checked cable is free when not connected- okay ( a relatively new cable).
Readjusted link rod so mixture increase (jets come down) start on each carby at same time. Interestingly it needed to be shortened to its minimum length to achieve.
Checked throttle increase cam fo free movement (all okay - on the middle hole).
A little better but still very stiff!!
Any comments and how far should the jets lower for cold starting?
(H4 carbies with teflon O rings on the main jets)
Mike
Mike Ellsmore

This is cold for us in winter!
Mike

Mike Ellsmore

Maybe this a John Twist video will help.

https://m.youtube.com/watch?v=inuK8oHHHPc

Jim
JL Cheatham

Mike, Have you got the engineered clearance on one of the actuating arms that gives you the first stage fast idle, second stage jet lowering function. One of the holes on the lever (cant remember which one)is very loose on the pin. I thought it was wrong many years ago and made the hole smaller and tighter on the pin. Choke was then really tight as per your symptom.

Alan
AR Terry

Thanks Alan,
Mine has the correct fast idle clearance holes. It is the next step when it is hard - when pulling down the jets. Checked another MGA at the weekend and his setup is similar to mine yet his is easy to operate - strange. It can only be cable snagging somewhere, mixture lever spring strength or main jet seal friction (I disconnected the fast idle cam and it is same with or without it connected.
Mike
Mike Ellsmore

Mike - Have you seen the John Twist video, number 201? At about 3 minutes 30sec, he explains one thing that can sometimes jam it, much easier for you to watch than for me to explain! It might anyway give you an idea. Good luck, Graham
Graham V

Thanks Graham and Alan - I did have a look at the video and will check if the cable stop arm is directly over the connection point as John mentions. My A being a right hand drive means the choke cable is where the starter cable is in John's video (actually a shorter straighter route to the carbs). Also my choke cable locks when turned clockwise from inside the cabin. Mike
Mike Ellsmore

Sorted! It was the locking mechanism for the knob - while it worked great when not connected to the the mixture control levers when connected it was jamming for some reason - after checking everything else again and then trying again I noticed a slight grating noise from the knob locking area. Pulled out the cable, blew it out with air and added some Loctite anti-sieze to the area, now works fine. It locks if you turn either clockwise or anti-clockwise -( it was a new aftermarket choke cable assembly that was a problem from the start).
Mike Ellsmore

This thread was discussed between 23/06/2017 and 27/06/2017

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.