Rough start - choke question

[Socrates]

I’ve discovered that the butterfly on one of my carbs is not closing completely when the choke is on, causing a rough start. Unfortunately, it’s not as simple as adjusting the spring tension to synchronise its operation with the other carb because there’s play in the linkage between the butterfly and the spring below. The play appears to be at the bottom of the linkage where it connects with a circlip to a lever attached to the bimetallic spring. There’s no sloppiness in the linkage of the other carb.

Here’s a picture from the internet showing the choke linkage:

I’m trying to identify which lever on the parts diagram the above linkage connects to below. I suspect it could be #6 below - am I correct?

Has anyone else had this issue, and if so how did you fix it?


Thanks

 

[stphers]

If you pop off the clear/white cap on the side of the carb, you will see the end of that rod that attaches to the choke flap. There is a small allen head screw holding the rod in place. You can loosen this and get some adjustment on the choke flap The choke flap should be set with a 2mm ( drill bit ) making a gap between the choke flap and wall of the carb You can also adjust both the tension and flap opening by loosening the 3 screws on the choke housing and change the flap setting You need the space between the choke flap and the carb body because the carbs have a vacuum break to open that flap a little to allow air to get into the carb on cold starts You should disconnect the linkage so each carb can be set up individually Fast idle should set on each carb for about 1700 rpm, when everything is reconnected , the carbs should run at about 1400 rpm for a fast idle

Thanks, Rick

 

[Socrates]

Thanks for your response. Are you suggesting that the allen screw will reduce the play in the butterfly, or that I should try to compensate for it by adjusting the gap to one or other side of the loose movement of the butterfly? In case I didn’t explain it well, there’s about 5deg of free movement in the butterfly.

 

[tdgray]

He is saying you need to go through the exercise of setting them both. Yes that screw adjusts the flap but to make sure all is well and working in tandem you have to do the settings correctly.

That should clean up your settings and “reset” your movement. Everything has a bit of natural wear and adjustment.