Are you experiencing rough running on your auto choke car?
Is your idle speed all over the place when warming up?
Is it difficult to tune your car so that is it neither too rich or too weak?
Due to the fuel of today being very different in composiiton to that of yesteryear when these cars were deisgned and built, many people are experiencing problems with the autochoke mechanism on their car. This is largely due to the fact that the new fuel causes the O ring seals in the stepper motor to swell and stick/split/perish. If new seals are purchased from Rover exactly the same symptoms are observed as these O rings are still made from rubber.
However there are O rings available to resist the new fuels. The size is BS013 and the material they need to be made from is Viton.
The seals are simple to fit. Simply unscrew the three screws that attach the stepper motor to the carburettor, withdraw it, and you can pull the old seals from the spindle and replace with new ones. When refitting apply some grease to the threads of the screws. The engine may need to be re-tuned after this operation particularly if the old seals have split but this is again an easy task. If the screws come out easily then the job should take no longer than 10-15 minutes.
If the screws fail to come out easily then the tops of the screws can be carefully drilled/ground off and the stepper motor withdrawn. After this there is plenty of screw left to grip with grips etc to wind them out so they can be replaced with new well greased ones.
When completed the auto choke should operate smoothly as it was first designed to.
I am able to supply replacement O-rings,which can be purchased through this website. Please use the contact form to request an order for some. Also most good oil seal suppliers will be able to get you some.
The price is £1 per pair including postage. Substantial discounts for multiple quantities are available.
Price list:
1 pair = £1
2 pair = £1.50
3 pair = £2.00
5 pair = £3.00
10 pair = £5.00