Ryobi P546 / P546A Chain: Size, Part Number and Fitting

One bar, one chain

The P546 ships with one bar length, 10”, and the manual’s bar and chain table has a single row: bar 311278001, chain 693814001, 40 drive links, 3/8” low-profile pitch on a 5-tooth sprocket (p. 29). RYOBI’s support page for the P546A links this same P546 manual, so the table covers both.

There are two RYOBI numbers for the chain. 693814001 is the service part in the manual and the repair sheet. RY10C1 is the boxed chain RYOBI sells: 3/8” low profile, 0.043 gauge, 40 drive links, filed with a 5/32” file. RYOBI’s P546A page calls it “Y40 .043"".

The gauge question. The 2019 manual prints .050 in. as the chain gauge. RYOBI’s current product page, the RY10C1 listing and Oregon’s part finder all give .043”. If you still have the old chain’s box or the bar, check the gauge stamped on it before you buy.

Changing the chain

The bar is held by one chain cover screw, and the hex key for it clips into a storage spot on the saw (manual pp. 23–24):

1. Take the battery out and wear gloves.
2. Use the hex key to remove the chain cover screw, the washer and the chain cover.
3. Lift off the bar and chain, and take the old chain off the bar.
4. Lay the new chain out in a loop with the cutters facing the direction of rotation. If they face the wrong way, flip the loop over.
5. Fit the drive links into the bar groove, leaving a loop at the back. Wrap that loop around the sprocket and set the bar flat on the mount with the bar stud in the long slot.
6. Make sure the chain tensioning pin sits in the tension pin hole in the bar. RYOBI warns the chain can come loose if it doesn’t.
7. Refit the cover, washer and screw finger tight, so the bar can still slide.

When you change the chain, look at the drive sprocket too. RYOBI says to have a worn or damaged sprocket replaced by a RYOBI service dealer (p. 26).

Setting tension

Turn the chain tensioning screw clockwise until the chain seats on the bar. Lift the bar tip, check for sag, then turn the screw 1/2 turn clockwise and check again. Repeat until the sag is gone. Hold the tip up while you tighten the cover screw (p. 24).

A cold chain is right when there is no slack under the bar and it still turns by hand without binding. A warm chain is right when the flats on the tie straps hang about .050 in. out of the groove. If the chain is too tight to turn, loosen the cover screw and back the tensioning screw off 1/4 turn (p. 25). New chains stretch, so check often at first. A chain set while warm can be too tight once it cools.

When a new chain doesn’t fix it

The manual’s troubleshooting table (p. 29) points to the usual causes:

• Bar and chain run hot and smoke: the chain is too tight, or the oil tank is empty. The P546 uses a push-button oiler: press the oil tank cap once before you start and once every few minutes while cutting (p. 15).
• Motor runs but the chain doesn’t move: the chain is too tight, or the bar and chain are damaged.
• Worn bar: replace it if the rails are spread, cracked or bent, or so worn the chain leans over sideways. RYOBI says to flip the bar weekly to spread the wear and grease the nose through the lubricating hole (p. 28).

The saw is built for pruning and limbing. RYOBI says it is not designed for trees over 7 in. in diameter (p. 16).

Sharpening

Use a 5/32 in. round file in a holder, kept level with the top plate. File at the middle of the bar with the chain tensioned (p. 26). The top plate angle is 30° and the side plate angle 80°, which the right file size gives you on its own (p. 27). Check the depth gauges each time you file: RYOBI specifies .025 in. clearance, set with a flat file and a .025 in. depth gauge jointer (p. 28). If the cutters hit nails, stones or dirt, RYOBI recommends having a service dealer sharpen the chain.