Black & Decker GH900 TYPE 1 trimmer Parts

A string trimmer and a line trimmer are the same tool in most everyday use; both cut grass and weeds with a fast-spinning nylon line. Your Black & Decker GH900 uses round nylon cutting line and can also convert to edging mode for lawn edges.

What each name usually means

• Line trimmer: Emphasizes the replaceable nylon line (the “cutting line”) on a spool.
• String trimmer: Common nickname for the same nylon-line tool.
• Edger mode: Some trimmers (including GH900) rotate the head to edge along sidewalks and beds.
• Brush cutter: A different category; often uses heavier line or metal blades for thicker growth.

GH900 specifics that help clarify the terms

The GH900 is a nylon-line trimmer with an automatic line feed system. It’s designed for trimming and maintenance edging, not for trenching or heavy brush cutting.

Feature	What it means on GH900	Why it matters
Cutting media	.065 in (1.65 mm) round nylon line	Using the right diameter helps feeding and cutting performance
Feed method	Automatic feed (do not bump to feed)	Bumping can cause poor feed and extra wear
Modes	Trimming and edging (head rotates 180°)	Cleaner edges without a separate dedicated edger

Why it matters when buying line and using the tool

Using the correct line type and operating angle helps the trimmer cut cleanly and reduces line breakage.

• Use .065 inch round nylon line for the GH900.
• Cut with the tip of the line and keep a 5° to 10° cutting angle.
• Keep the guard in place and maintain at least 24 inches between the guard and your feet.
• In edging mode, keep bystanders and pets at least 100 feet away.

For operating details, edging conversion, and safety guidance, follow the GH900 owner's manual.

Last updated: February 2026

To change the cutting line on your Black & Decker GH900 line trimmer, unplug it first, remove the spool cap tabs, lift out the spool, then install a new spool or rewind .065-inch round nylon line and feed it through the eyelet before reseating the spool.

Safety first (do this every time)

• Unplug the trimmer before changing the spool or line.
• Wear eye protection that meets ANSI Z87.1.
• Clear the area of wire, cord, and string-like debris that can tangle in the head.
• Use only the correct line size to avoid overheating the motor.

Replace the spool (fastest method)

1. Unplug the trimmer.
2. Press the two tabs on the spool cap and remove the cap.
3. Pull the empty spool straight out.
4. Clean grass and dirt from the spool housing.
5. If the internal lever in the base of the housing is out of place, set it back correctly.
6. Guide the line end into the eyelet.
7. Push the new spool onto the boss and rotate slightly until it seats.

For this model, the manual specifies a Black & Decker replacement spool model AF-100 and replacement cap RC-100; the cutting line should stick out about 5-3/8 in. (136 mm) after installation.

Rewinding line (if you are using bulk line)

Use .065 in. (1.65 mm) round nylon line.

Item	What to use	Why it matters
Line diameter	.065 in (1.65 mm) round	Prevents motor overload and overheating
Spool option	AF-100 prewound spool	Quick, consistent feed
Cap option	RC-100	Helps secure the spool and line

Why it matters

Correct line diameter and proper spool seating help the GH900 feed line smoothly, cut efficiently, and reduce nuisance issues like overheating, poor trimming performance, or rapid line wear.

For diagrams and the exact head parts callouts, follow the steps shown in the GH900 owner's manual.

Last updated: February 2026

For the Black & Decker GH900 electric line trimmer, we use .065 inch (1.65 mm) round nylon line. Using the correct diameter helps the Auto Feed System work properly and prevents motor overload and overheating; see the GH900 owner's manual for line and spool details.

Recommended line type for GH900

Use line that matches these specs:

• Diameter: .065 inch (1.65 mm)
• Shape: round
• Material: nylon
• Feed system: automatic (do not bump the head to feed line)

Why the exact size matters

Using the wrong line size changes how the trimmer cuts and how hard the motor has to work.

• Thicker or serrated line can overload the motor and cause overheating
• Incorrect line can cause poor auto-feed performance
• Wrong line can increase line tangling and uneven feeding

Quick spec check

Item	What GH900 uses	What to avoid
Line diameter	.065 in (1.65 mm)	Heavier gauge line
Line shape	Round	Serrated or specialty shapes
Feeding method	Auto Feed System	Bumping the head to feed line

Helpful tips to reduce line wear

Line wears faster when edging along abrasive surfaces (like sidewalks). We recommend:

• Keep the cutting line over grass or dirt, not over concrete
• Use the wheeled edge guide when edging so auto-feed works correctly
• Slightly tilt the trimmer for a closer cut (instead of forcing the head down)
• Trim heavy weeds in lighter passes to reduce drag on the line

Why it matters

Correct .065-inch round nylon line protects the GH900 motor, keeps the Auto Feed System consistent, and reduces downtime from frequent reloading.

Last updated: February 2026