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Adjusting mixture
Posted: Tue Aug 18, 2015 9:19 pm
by captain
Could anyone please tell me how to set the mixture on a 1991 cooper last of the carb type,I removed the tamper proof plug but it doesn't seem to have a slotted screw in there thanks in advance
Re: Adjusting mixture
Posted: Tue Aug 18, 2015 10:27 pm
by rich@minispares.com
It should have the screw, but you need a very wide fat blade to turn it as they can be mega tight, they also chew the slot up in the screw really easy.
Don't forget that it's opposite to the early carbs, so its in to rich, out to weak
Re: Adjusting mixture
Posted: Wed Aug 19, 2015 3:07 am
by mini63
I think with HIFs you also have to run the engine at 3000rpm to cool the fuel in the bowl before setting mixture and then set the mixture within 1-2 minutes.
Re: Adjusting mixture
Posted: Wed Aug 19, 2015 10:52 am
by ianh1968
mini63 wrote:I think with HIFs you also have to run the engine at 3000rpm to cool the fuel in the bowl
before setting mixture and then set the mixture within 1-2 minutes.
I have never heard this before...
... but I do know that there is a bi-metalic "thingy" which is part of the self-adjustment
system for these carbs. The "cooling the fuel" fuel concept would most likely be
something to do with this.
I am fairly sure that this would not have anything to do with being able to locate and
turn the appropriate screw.
Still very valid and worth remembering as far as actual calibration goes, though!
SHAMELESS PLUG:
This needle selection utility is available on the main MK1 site...
http://mk1-performance-conversions.co.u ... l_carb.htm
Ian
Re: Adjusting mixture
Posted: Wed Aug 19, 2015 12:00 pm
by surfblue63
How to set up an HiF from the Rover manual
Re: Adjusting mixture
Posted: Thu Aug 20, 2015 4:23 am
by mini63
ianh1968 wrote:mini63 wrote:I think with HIFs you also have to run the engine at 3000rpm to cool the fuel in the bowl
before setting mixture and then set the mixture within 1-2 minutes.
I have never heard this before...
... but I do know that there is a bi-metalic "thingy" which is part of the self-adjustment
system for these carbs. The "cooling the fuel" fuel concept would most likely be
something to do with this.
I am fairly sure that this would not have anything to do with being able to locate and
turn the appropriate screw.
Still very valid and worth remembering as far as actual calibration goes, though!
SHAMELESS PLUG:
This needle selection utility is available on the main MK1 site...
http://mk1-performance-conversions.co.u ... l_carb.htm
Ian
I can recall late MGBs Ian running twin HIFs the factory steps required running the engine to cool the fuel for just that, the bi-metallic jet for temp compensation in the bowl.
just part of the mixture setting up.
fussy things.