I'd like to know the best practice technique for drilling a carburetor jet.
I bought an RV-6A with an O-320-E2D, FP, MA-4SPA carb. It was running overly rich when I bought it (had to lean for takeoff at SL), so I elected to rebuild the carb myself. I replaced the main jet and tube with the same P/N, but noted at the time that the new jet was considerably smaller than the old one, which had apparently been drilled out.
Now it is running too lean, as evidenced by high EGT and very little rise to peak EGT.
Can I just use a standard numbered drill, or should I get some small reams? Any advice on how to calculate how much to enlarge the jet, or just go in little steps and test it each time?
I understand that some jets are "stepped", and that drilling them out can cause major changes in fuel flow with only small increases in drill size.
Any and all ideas are appreciated.
Here is a very good article on carbs from AMT online: http://www.amtonline.com/publication/article.jsp?pubId=1&id=1024
I bought an RV-6A with an O-320-E2D, FP, MA-4SPA carb. It was running overly rich when I bought it (had to lean for takeoff at SL), so I elected to rebuild the carb myself. I replaced the main jet and tube with the same P/N, but noted at the time that the new jet was considerably smaller than the old one, which had apparently been drilled out.
Now it is running too lean, as evidenced by high EGT and very little rise to peak EGT.
Can I just use a standard numbered drill, or should I get some small reams? Any advice on how to calculate how much to enlarge the jet, or just go in little steps and test it each time?
I understand that some jets are "stepped", and that drilling them out can cause major changes in fuel flow with only small increases in drill size.
Any and all ideas are appreciated.
Here is a very good article on carbs from AMT online: http://www.amtonline.com/publication/article.jsp?pubId=1&id=1024