Hi, the entire cutting head fell off/ out of the shaft housing on my Bolens trimmer BL110.there is a square bolt that goes into a fitting on the cutting head but it will not stay secure. As always it fell apart when in use and for the life of me I could not locate any pieces that appeared to come from the trimmer, nor does it have any sort of detailed assembly diagram in the manual.How do I fix this? Am I missing a piece?

Make sure you have the head correctly located and affixed. If you have, return it.

BOLENS BL110 OPERATOR'S MANUAL Pdf Download ...

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Summary of Contents for Bolens BL110. Page 1 BL110 2-Cycle Trimmer Operator's Manual Removing Unit From Carton Assemble The Unit No Tools Required!

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Hi!

Please check the manual to this trimmer:

Hope it will help! https://manualsbrain.com/en/manuals/804363/?page=2

The curved shaft machine has a flexible drive shaft like a speedo cable, slacken the two tube pinch bolts, these are accessed on the r/h side of the grey plastic handle through holes in the plastic housing,, remove the two mushroom headed screws either side of the plastic handle,don't lose the black o rings under the screw heads, do not remove any of the plastic housing screws, now carefully draw the tube out through the plastic handle/trigger assembly, once out pull out the old drive shaft, grease the new drive shaft and push back into the tube, once fully in turn the end to make sure the trimmer head turns, now feed the tube back through the trigger housing, make sure it is fully back home and the square end of the new shaft has entered the square hole in the drive drum, re tighten the pinch bolts, start the engine, if the head does not turn, slacken the pinch bolts and push the tube further in, re fit the two mushroom headed screws.

if you want to put in new trim line
the knob is left hand thread so to get it off you will have to turn it as it you are doing it up
if you want the whole head of the shaft , there will be a clamp/screw/retaining bolt that you remove and pull the whole lot off the shaft

Check the drive shaft. Within the drive tube there is a tightly sprung drive shaft, check where this connects to the head of the cutting attachment, it could have a worn drive.

http://www.ereplacementparts.com/mtd-bl110-41ad110g965-trimmer-parts-c-20039_20040_143532.html

Hi Brianna,here's a link to your specs,it says to use 40;1,so 50'1 will not work. Bolens25cc 2 Cycle 17 in Curved Shaft Gas String Trimmer

Adjust carb. Initial adjustment is 1 full turn out on both low and high side. If it still fall on it's face, turn the low side out and additional 1/4 turn.

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.

to much dirt got up in clutch housing and shoes are not making full contact unit needs to be dissembled and cleaned.

Could be blocked spark arrestor or carboned up in the exhaust port.