Is the main jet (the one screwed into the bottom of the carb inside the float bowl) the only difference between 340 and 390 honda gx series carburetors? My 340 needs a new carb and i have a good 390 carb. Can i just switch the jet out and install it on the 340 or is there another difference?
As I know it, the carb is just slightly larger, the 390 cam has a little more duration and lift, the 390 has about 50 more cc's...for the most part, very similar. When I build a 340 up, I put in a 390 cam, carb...makes a decent little engine.