Ok, got s chance to take some picts to help run through this stuff -
On both brushes, these will be things to check. On the one that paint will start flowing right away with trigger push - there is no alternative to the needle is not sealing within the nozzle (for one reason or another) I am going to assume there is some sort of debris inside the nozzle. I would fill the cup with either cleaner, or water, and start spraying. At the same time, loosen the needle chuck, and draw the needle back by pulling on the back end of it - maybe about 1/8th inch. Push it back in with a slight twisting motion. Repeat several times to see if you can stop the flow of spray when the needle is all the way in. If the spray stops, tighten the needle chuck, and you should be good to go. This will sometimes help to expel debris easier than just spraying...
On the other, there are several things to check. Sometimes air can leak from the head assembly where it mates to the body. If the leak is big enough, it will hinder performance. I check this by putting a drop or two of cleaner (or soapy water) at the seam where the two meet, and apply air by pushing down on the trigger. You will see bubbles like this pict -
View attachment 46777
If you have bubbles, either add teflon tape to the threads, or an old trick is to use bee's wax (chapstick will work also).
Next to check is the nozzle, as paint flow is generated by a vacuum caused by airflow over the very tip of the nozzle. You will want the tip of the nozzle to be at least flush with the air cap, or even better, protruding just past the face of the air cap.
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If the nozzle is below the face of the air cap, it can allow air to enter the tip, causing back pressure. The option here to correct, is use the tip wrench to loosen the nozzle a little (this may then allow a vacuum leak at the base of the nozzle, which may be corrected with bee's wax or chapstick
) You may also try replacing with another nozzle, as there is a fair bit of tolerance (or slop) in the brushes within this price range. This brings me to the next area to check - the base of the nozzle. If air is allowed to pass this critical area, you will have a problem
. It is possible the tiny o-ring is cut, or mangled, so I would be tempted to eliminate the possibility of leak here by using wax or chapstick on the nozzle threads (careful not to allow either to get into the nozzle, just on the threads)...
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The other thing to look for will be the nozzle alignment with the air cap. The tip of the nozzle should ideally be centered in the opening of the air cap.
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On several of the brushes I have of this type, I have been able to loosen the nozzle with the tip wrench, and then snug it back down while pushing in the direction I wanted it to go. Might take a few try's, but I have been able to get them at least much closer...
I hope this helps, and that you are able to identify the issue, and get yourself back into the game asap!