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MG MGB Technical - Choke Cable Routing

Can anybody tell me the route for the choke cable for a later car running HIF4s?

The reason I ask is that my car had HS4s which require the choke cable to enter from below. I had a ratty old pair of HS6s on there until recently, they required the choke cable to come up from below too. The cable goes through a hole in the right hand side of the passenger footwell, a few inches below the level of the little 'shelf' upon which the remote servo sits in the engine compartment.

I've just got a new set of HS6s, and they require the choke cable to approach from above like the HIF4s.

Can anybody tell me which way the choke cable goes? The present route is too long and too tortuous. I've got a later choke cable.

Thanks,

Neil
Neil22

Neil. Take the cable across to the left footwell with a nice curve behind the dash , then pass thro bulkhead using same hole as screenwash pipe. This will allow a gentle curve over the rear carb to connect up with the linkage. Jim
jim soutar

I'm not sure it's the carbs that make the difference, it is the bracketry. Both types of carb work the same way, that is the choke lever on the linkage has to be moved upwards to apply enrichment. This is why the earlier system had the fixed inner and the moving outer when it came up from below, whereas the later carbs had the more normal fixed outer and moving inner. But if you have the later bracketry and linkages then you may well need to bring the cable in from above, or modify it to allow the cable to come up from below. Clausager has pictures.
Paul Hunt 2

Paul,
You are right, the old set had a lever on the choke interconnecting shaft for the outer and a spindly bracket on the car for the inner. The new one has a ferrule on the carb body for the outer and the inner fits directly to the choke lever on the same carb. The system on the old set was not entirely satisfactory, the angles were not quite right and there was not enough leverage, especially since I have additional springs attached to the throttles (for motorsport). The newer system should be much more satisfactory. I guess I'll find out soon enough... It's just that the choke cable will not reach!

Jim,
I'll try that route and report back in a few days.

Thanks both,
Neil

Neil22

One thing not mentioned in the manuals I have seen regarding the older 'up from below' routing does concern angles. Unless the cable makes close to a right-angle with the operating lever when the choke is *half* pulled, you can get very stiff operation or incomplete movement. Also the routing of the cable should be such that it is free from obstructions in both the released and pulled positions, as the outer moves between the two.
Paul Hunt 2

There are two holes in the bulkhead; one for the washer tube and one with a plastic grommet. I'm going to move the washer tube from one hole to the other (might even move the washer botle to somewhere more sensible - there's more water in the tube than in the bottle!) and use the washer pipe hole for the choke. Should reach okay. I would have known by now, if it hadn't taken the best part of an hour to get the old one off... the nut is 3/4", and 3/4" spanners are not made for working behind the dash!

The HS6s (old and new) have throttle return springs 'built-in' as opposed to separate as on the HS4s. Even so, scrutineers insist on seeing another two - and four springs makes for a lot of return force. Trying to counteract them with the choke operating on a cam is almost impossible...

Neil
Neil

This thread was discussed between 11/01/2008 and 13/01/2008

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