Quick question re HS2's - 3 springs...
Discussion
1968 Morris 998cc with twin HS2's
Just a quick question. My HS2's have three springs fitted to the centre connecting rod/spindle. I'm assuming the two on the outside go to the chokes and the centre one is the throttle return spring? My mechanic (USA - not exactly Mini Central) over here fitted them with the centre spring to the LH carb choke(assumed) and the LH spring to the centre throttle return.
Result - the left hand spring is sitting on the manifold!!
Could this be why the revs don't drop when engine hot - c.1500-2100 rpm..... ?????
Thanks
Just a quick question. My HS2's have three springs fitted to the centre connecting rod/spindle. I'm assuming the two on the outside go to the chokes and the centre one is the throttle return spring? My mechanic (USA - not exactly Mini Central) over here fitted them with the centre spring to the LH carb choke(assumed) and the LH spring to the centre throttle return.
Result - the left hand spring is sitting on the manifold!!
Could this be why the revs don't drop when engine hot - c.1500-2100 rpm..... ?????
Thanks
Answer to my own question which begs another: below is a picture of another set of HS2's I just bought. Is the bracket at the bottom part of the heatshield assembly where the springs link to the right way round? if the answer is 'yes' then the set fitted to my car a the moment have been assembled incorrectly!
the chokes dont need the springs (they have their own built in ones), all three are used on the throttle.
the outer two ensure that each carb butterfly is able to be sprung shut (when the throttle isnt pressed), the middle one (not always used) is to make sure the cable tugger is pulled fully back down - though the use of this depends on the linkage, manifold and throttle cable position.
if your only using the middle spring on the cable tugger, then the butterflys will be able to open them selves to the extent of the free play that exists in the throttle linkage between each carb and the tugger bracket (there is free play built in to allow for balancing the carbs), this small amount of free play will allow the revs to fluctuate by a 1000 rpm or so
to make sure the springs are correct disconect the middle one, then loosen the nuts holding the throttle tugger rod (you will need to balance the carbs after this). now you are in a position where the throttle tugger and the cable will have no affect on the rpm as its disconected, each carb should have one spring going to its butterly rod to make sure the butterfly stays shut - you can test this by prodding the linkage with a screwdriver.
if you are happy with this get someone to start the car (helps if its warm) - your best standing over the engine with the means to cut it if the springs are wrong and the revs climb (bit of string round the coil lead, or something like that) once its started and ticks over at, say, 1000rpm, balance each carb, then tighten the tugger linkage back up. now turn it off and reconnect the middle spring to the tugger.
if the heat sheild is hitting the manifold (it will if its a tubular one) all you have to do is bend it a little - unless (like me (!)) your using a sprite manifold and there is no room for a heat sheild or provision for springs - then its starts getting a little more complicated!!!
the outer two ensure that each carb butterfly is able to be sprung shut (when the throttle isnt pressed), the middle one (not always used) is to make sure the cable tugger is pulled fully back down - though the use of this depends on the linkage, manifold and throttle cable position.
if your only using the middle spring on the cable tugger, then the butterflys will be able to open them selves to the extent of the free play that exists in the throttle linkage between each carb and the tugger bracket (there is free play built in to allow for balancing the carbs), this small amount of free play will allow the revs to fluctuate by a 1000 rpm or so
to make sure the springs are correct disconect the middle one, then loosen the nuts holding the throttle tugger rod (you will need to balance the carbs after this). now you are in a position where the throttle tugger and the cable will have no affect on the rpm as its disconected, each carb should have one spring going to its butterly rod to make sure the butterfly stays shut - you can test this by prodding the linkage with a screwdriver.
if you are happy with this get someone to start the car (helps if its warm) - your best standing over the engine with the means to cut it if the springs are wrong and the revs climb (bit of string round the coil lead, or something like that) once its started and ticks over at, say, 1000rpm, balance each carb, then tighten the tugger linkage back up. now turn it off and reconnect the middle spring to the tugger.
if the heat sheild is hitting the manifold (it will if its a tubular one) all you have to do is bend it a little - unless (like me (!)) your using a sprite manifold and there is no room for a heat sheild or provision for springs - then its starts getting a little more complicated!!!
Edited by guru_1071 on Sunday 11th October 19:28
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