mixture screw adjustment

[jgreg53]

My 48 p15 has the b and b carb.  I've rebuilt it twice. The last time was with the help of mikes carbs and his video.  Why do I have to run the mixture screw down to just before bottoming out to get the idle to smooth out? Is this a characteristic of this carb?

Edited February 1, 2019 by jgreg53

[Plymouthy Adams]

what is the baseline setting of your throttle plate/airhorn ?

[jgreg53]

I'm not familiar with that.

[DJ194950]

I believe that Plymouthy is asking is does your throttle plate close all the way tightly?

 

If not you will probably have the situation you describe.

 

Look down into the carb. and see if the throttle plate closes tightly to the bore of the carb inlet??

 

Is the throttle linkage adjusted to where it can close.?

 

Did you remove the throttle plate and reinstall it upside down? (it has a beveled edge on it to close tightly.)

 

Just a couple of things to look at that easy to check.

 

DJ

[jgreg53]

I will check that out. Thanks DJ

 

[jgreg53]

I checked the throttle plate. It seems to close fine. Can it be installed upside down?

[DJ194950]

Yes but only if you removed it.

 

Open the throttle all the way open with return spring on the throttle linkage removed and with a light look inside the carb throat and you can see the beveled edge on the upward side. I thinks the lower edge is also beveled but may be harder to detect. I would actually have to go look to  my carb. on the car to say 100 %

 

DJ

[jgreg53]

If the 2 small screws holding the flap are on top, then the flap is right. Looking down at the flap i see the 2 small silver screws. The heads of the screws, anyway.

 

Edited February 2, 2019 by jgreg53