HOW TO USE A DREMEL TO NOTCH A 4 X 4 - Dremel Variable - Speed Multipro Rotary Tool 395

A photo would help. If it is what I am thinking of (what looks like a flat heat screw with a dimple in the middle of the slot) you can take an old, small flat head screwdriver and file a notch in the blade to make it work. A Dremel tool works good for making this notch.

Bolens trimmer sputters and stalls and only runs on half choke? Here's how to fix it.
Look on the top of the carburetor and you will see 2 black screws that are mostly round with a flat side recessed in the aluminum housing. They are flat on top and have no notches to insert a screwdriver. The trick is to turn these two screws 1/4 turn counterclockwise. I have a set of precision pliers and used the fine tipped needle nose to turn them.
The other option is to try and notch the top of them enough so you can use a flat blade screwdriver. You can grind down the surrounding aluminum with a Dremel tool so you can access them better.
You can see in the picture that I scratched across the top of the screws as a reference to see how far I was turning them.

I used a Dremel cut wheel to notch both screw heads for a standard screw driver. Had to notch the protruding side covers around the screws on the carb that prevent access to the screws as well, be careful not to cut into carb or surrounding hardware, thus preventing damage to unit. It works like a champ after fine tuning carb don't even need to choke it for starting.
With the added ethanol in some gas now most carburetors need a little fine tuning or it won't run efficiently.

dremel have a collet adaptor to cater for this problem. They are available from the dremel dealer or hardware store

Bolens trimmer sputters and stalls and only runs on half choke? Here's how to fix it.
Look on the top of the carburetor and you will see 2 black screws that are mostly round with a flat side recessed in the aluminum housing. They are flat on top and have no notches to insert a screwdriver. The trick is to turn these two screws 1/4 turn counterclockwise. I have a set of precision pliers and used the fine tipped needle nose to turn them.
The other option is to try and notch the top of them enough so you can use a flat blade screwdriver. You can grind down the surrounding aluminum with a Dremel tool so you can access them better.
You can see in the picture that I scratched across the top of the screws as a reference to see how far I was turning them.

Look for a small notch behind the brass fitting that the brushes slide into.

Try at eReplacementParts.com : Power Tool Parts and Tool Repair Diagrams or Dremmel.

If you need more help come back.Post / thumbs / testimonial are welcome!

Link to Manual: Dremel Scroll Saw 571-5

On either side of the switch is a black disk with a notch small enough for a small screwdriver. Unscrew it and take it off to expose the spring. Gently pull the spring out and the brush should be attached. If you encounter resistance, then you may disconnect the spring from the brush. If this happens then push the spring back in and hope you catch the brush; if this does not work, then get creative or take the whole thing apart to get to it. After that, just put the new brushes in and recap.