How to change the cutting line in a curved shaft fs45 *******

did you change the Spool assembly from the original? The Straight shaft trimmers turn counterclockwise and the curved shaft trimmers turn clockwise. If you put a Straight shaft spool on a curved shaft machine, it will unscrew itself. and Vise verse.

is the drive cable between the engine and the head broken?

Unscrew the head's center bump-knob counterclockwise with your fingers. Pull the bump knob off and take the spool cover off the head. Slide out the spool and any remaining cutting line. Lift out the spring underneath the spool. Take out the slide washer. Unscrew the arbor bolt either clockwise or counterclockwise, depending on model, in the center of the trimmer head using the wrench. Take the entire head off the end of the shaft.

Here is the info from the manual, the replacement line is put in near the center of the spool on the top of it, you simply feed it in. I have included a link to the manual so you can see the pictures. Look at page 10 for these instructions.
http://www.weedeater.com/ddoc/WEEO/WEEO2009_USen/WEEO2009_USen_TE475-952711797_545186833.pdf
LINE REPLACEMENT Pre--wound spools offer the most convenient method for replacing line and ensuring optimum performance. S Replacement spools are color--coded to ensure use of the correct spool with your unit. Be sure to use the same color spool as the existing spool. NOTE: Always clear dirt and debris from cutting head components when performing any type of maintenance. S Hold spool and unscrew cap by turning in the direction shown on top of the cap. S Remove line guide ring and spool. NOTE:When removing and/or installing spool, ensure dust cup remains installed over shaft. Use a pre--wound spool or refill spool with line. If using a pre--wound spool, remove tape strip from line and spool. REFILLING THE SPOOL WITH LINE WARNING: Use only 0.080" (2 mm) diameter round line. Other sizes and shapes of line will not advance properly and will result in improper cutting head function or can cause serious injury. Do not use other materials such as wire, string, rope, etc. Wire can break off during cutting and become a dangerous missile that can cause serious injury. 1. Cut a length of 25 feet of 0.080" (2 mm) diameter round WEED EATER brand line. Feed line in direction shown on spool. Spool 2. Insert one end of line into center cavity of empty spool. Ensure line will feed into spool in the direction shown on the spool (counterclockwise). 3. Continue feeding line into spool, leaving 4 -- 6 inches (10 -- 15 cm) unwound from center of spool

Take a length of about 6 foot of line, kink it in the middle and pass this through the hole in the spool. Wind the two lengths of line around the spool in their own divisions and in the same direction. The direction of wind is embossed in the reel and the line should be wound tightly and held all the while. When you have about 6-8 inches left in your hand, bring the cover up to the spool and carefully pass the two ends of the line through the holes, push the cover all the way over while pulling on the two pieces of line and ensuring that the lines stay on their own side of the division on the spool. Fit and tighten the bump nut and trim the lines to just about the cut-off blade.
The lines should trail out of the holes in the direction of the machine's rotation. Try cut with the tip of the line as much as possible. Cutting nearer the drum flexes the line and will lead to early breaking of the lines. Run the motor at a constant speed and rather move the cutting head in and out of the weeds to affect a deeper cut

You can buy new Line to re-spool on your existing head

Cut two separate pieces of string, about 7 ft. each.

Stick the end of the line in the hole on the inside of spool.

Wind clockwise onto spool, putting the line that is closest to the ground on first.

Once you have winded this piece on, lock the last 4 inches of line through the slits on spool.

Repeat process for second piece of line, locking the last 4 inches in slot opposite the other locked in piece.

Put the spool on the trimmer, feeding the end of lines through either hole on trimmer.

Before you push the spool all the way on, pull the strings out of the locked position.

Jim

Cut two separate pieces of string, about 7 ft. each.

Stick the end of the line in the hole on the inside of spool.

Wind clockwise onto spool, putting the line that is closest to the ground on first.

Once you have winded this piece on, lock the last 4 inches of line through the slits on spool.

Repeat process for second piece of line, locking the last 4 inches in slot opposite the other locked in piece.

Put the spool on the trimmer, feeding the end of lines through either hole on trimmer.

Before you push the spool all the way on, pull the strings out of the locked position. Put cap on and GO CRAZY!

Jim

So, is this trimmer suppose to feed the string automatically? If not, then it sounds like the string is wound up on the spool the wrong direction.

Jim