I have an RJH-08 carburetor that has been rebuilt for a '30. I am using it on a'29 engine and find it runs a little rough at speeds above an idle. Was there different jeting between '29 and '30? Also, how can I tell if it's a model 150?

Art M

More info I forgot in the last post: It only idles smooth with the idle adjustment screw turned all the way in. I know this is not right!

Art M

While there are differences in the jetting between the '29 and '30 versions of the RJH-08 carburetors there should not be a easily noticeable difference in performance.

It is not uncommon for the idle mixture screw to be screwed all the way in on these carburetors. Wear on the throttle shaft, air leaks at the low speed jet, erosion or corrosion in the carb body, plus a few other differences from original manufactured condition will cause more dilution air or reduced gas flow in the idle circuit. It can cost up to several hundred dollars ($$$$$) just to get some adjustment to the screw. If the carburetor can be made to idle properly then it is not cost effective to make the repairs. Obviously if it can not be made to idle properly then the cost is justified.

Chipper, Thanks for the reply. I guess I'll leave well enough alone for now. When I run out of other things to do, I may look further into it or have one of the VCCA carb experts go over it for me.

Thanks again.
Art M