I have a baby lock 418 serger (3 thread).i NEED TO KNOW HOW TO THREAD THIS MACHINE.

Try rethreading it using the order: 3, 4, 2, 1. If you are threading it in the wrong order it will give you problems. Afterwards, you will need to carefully adjust the tension controls. This can be done more easily using four different colored threads.

Hopefully you have the manual. It helps to use 4 different colors of thread so you'll be able to differentiate which thread is presenting a problem.

Just thread each thread as though it were the only one, like a sewing machine. Make sure you thread each in the proper order or it will most likely never work. AND ALWAYS RAISE the presser foot when threading and give each thread an extra little tug when going through the tension disk so the thread will seat completely.

Set the tension disks to the midway point, so they are all set about the same. Then test.

If something goes haywire, just bite the bullet, remove ALL the threads and start over threading from the beginning. Believe me, it very seldom works to try to re-thread only one thread...

It took me an entire day to get my new-used serger threaded properly. So don't despair... You might look around for a beginning serger class.

...

I highly recommend you watch the videos on YouTube. They explain as they are threading the machine and the images show you exactly what to do.
Best of luck!

I suggest changing both needles
and rethreading the machine
use a can of air that is used for computer keyboards on the inside
here's a link for parts to the machine and also has a manual
the manual should have information about the thread tension
http://www.sewingpartsonline.com/babylock-BL90-serger-machine-parts.aspx

contact babylock customer service about a manual

here's a tip I learned for sewing machine or serger

do one thread cone at a time-the cone or spool that's on the serger--cut the thread close to the cone-then remove the cone from the serger ,,don't remove the thread that you just cut from the serger,,now put your thread on the spindle & tie your thread to the thread that you just cut (make sure it's a small knot) now the thread that's in the needle pull until the thread that in the needle is your & then cut off the other thread & make sure to cut of the knot part & leave a thread tail of 4 to 6 inches

do each spindle this way

orange-(5-7)
yellow-(4-6)
green-(2-4)
blue-(2-4)
medium weight, 4 thread

You can buy the manual here. Sorry can not find free one for you.

http://www.thefind.com/query.php?query=Serger+Babylock+BL3+418+manual


Good luck and please rate

You have to get the replacement wires from a Babylock dealer, I did too then after sticker shock at the price of that wire I learned to make a thread cradle and use that to thread difficult threads no. Take about 24 inches of regular sewing thread and fold it in half, put the open ends (together, same legnth) into the jet air port and hold onto the loop end, press the jet air threader and it will thread the machine, insert the thread you want to use into the loop you have in your hand and pull it thru the machine using the ends of the thread you put thru the machine, sounds harder than it is and works all the time. No more spending $8 on replacement wires. You can use this method for all the jet air sergers.

I was in a similar position (but had the manual). The manual isn't as complete as I'd like. Anyway, what finally got mine working were the following:
1. turn all tensions to zero before putting thread through them
2. thread the upper looper, then lower looper, then needles.
3. when threading the lower looper (mine kept pulling out), after passing the thread through the looper eye, it needs to go pretty much straight up, not wrapping around anything else - other thread, for example. Mine was at one point trying to wrap itself around a post.
4.when everything is all threaded up, make sure all threads are under the foot *and* pulled to the left (even though the manual says pull to the back). Then chain off without fabric, turning the handwheel by hand to make sure loops are forming. If so, adjust tensions to where you think they should be (mine are currently all between 2 and 5), and add fabric. Then tweak as needed.

For me, this was a lot of trial & error, hair-pulling, and getting tips 1, 2, and 4. I figured out #3 on my own, with much swearing along the way. Good luck!

LF