simple choke question on BN2

[bighealeysource]

Simple question and looking at Norman Nocks "Tech Tips" I got from him 7 years ago - when you pull on your choke cable the carb jets should lower to enrich the mixture, correct ? While tuning my carbs noticed that the choke cable does speed up the engine but barely moves the jets when fully extended as now adjusted with the metal stirrup that hooks up both SU's. To work properly the stirrup should be adjusted so the jets lower, right ??? Know this seems like an obvious question but I usually try to practice "if it aint broke, don't fix it" and really have had no problems starting the Healey. But, if I need to do the above I can easily fix it while I have the cold air box off.
Thanks,
Mike

 

[57_BN4]

Hi Mike,

Yep it should lower the jets a good 1/4" or more when fully out. One thing I found recently is that the optimum height for the brass levers is quite different between the front and rear carb so if it all looks a bit drunk when working correctly then all good. I found the best way to set the lever height is to pull the choke out to the second click and set each brass lever to just be touching the jet but not pulling it down. Then once the screws are tight, adjust the fast idle screw to give about 1200 rpm hot or 8-900 cold.

That way you get a bit of fast idle on the first click which is useful for stinking hot days when the carbs start to flood and the idle goes low, second click for cold warm up and third-onwards click for actually starting when cold. I'm assuming your choke knob is original with the indentation clicks.

If you still have the original screws in the cable trunnions then be careful not to overtighten them as they are a ridiculous BSW thread that is so thin it snaps with even slightly more pressure than you'd put on a tiny screwdriver.

[edit] but if it is working fine as-is then no point changing it.

Andy.

 

[bighealeysource]

Thanks Andy, that's kind of what I thought should happen. And you're right about the jet levers, not level with each other at all. I am actually using a choke cable from an MGB that allows you to lock it in position versus the original choke cable that was long ago replaced with another one by a previous owner. Thanks also for the hint on the trunnion screws as you're right, they are mighty small and sure don't want to try to find a replacement for them.
Thanks again,
Mike