The STIHL FS 450 takes the NGK BPMR7A spark plug as its spark plug; Australian sellers list it from A$5.60 as of 3 November 2026. Fitment confirmed against the manufacturer's compatibility list.
Your line trimmer
STIHL FS 450
Line trimmer
Confirmed against STIHL's listConfirmed against STIHL's own compatibility list
Not yours? ChangeTakes the BPMR7A spark plug
BPMR7A spark plug · check the code on your old part before ordering.
STIHL's FS 300-480 manual names Bosch WSR 6 F, NGK BPMR 7 A or Champion RCJ 6 Y (not all markets); replace after 100 operating hours.
Your line trimmer
Line trimmer
Confirmed against STIHL's listConfirmed against STIHL's own compatibility list
Takes the BPMR7A
Spark plug · check the code on your old part.
STIHL's FS 300-480 manual names Bosch WSR 6 F, NGK BPMR 7 A or Champion RCJ 6 Y (not all markets); replace after 100 operating hours.
Other STIHL models that take the BPMR7A
GenuineGenuine NGK
$5.60
Power Mowers · 3 NovLowest genuine · Power Mowers · checked 3 Nov
CompatibleCompatible option
See seller
No compatible seller tracked yetNo compatible seller tracked yet
Genuine: made by NGK. Compatible: another brand.Genuine is made by NGK. Compatible is made by another brand. Check the seller's page for the size and models it fits.
Lowest price · $5.60
Power Mowers. Every seller we track is listed below. Some links earn us a commission. Some seller links earn us a commission, at no extra cost to you.
Compare 3 sellers
AUD, before delivery. Each price shows when it was checked.
Opens Power Mowers in a new tab. Their page is the source of truth for price, delivery and returns.
How long it lasts
Replace it after about 100 hours of use, or sooner if the electrodes are badly worn, STIHL's manuals say.
After replacing: No reset needed.
How to change the spark plug in your STIHL FS 450
Watch the guide or follow the steps.
- 1Stop the engine and let it cool. On a chainsaw, engage the chain brake.
- 2Take off the shroud or spark plug cover, then pull the boot off the plug.
- 3Clean any dirt from around the plug so nothing falls into the engine, then unscrew it with the combination spanner.
- 4Check the gap on the new plug: STIHL gives 0.5 mm. Adjust it by bending the side electrode carefully if needed.
- 5Screw the new plug in by hand until it seats, tighten it with the spanner, press the boot firmly back on and refit any cover you took off.
Every number this part goes by
- Retail name:
- BPMR 7 A
- Retail name:
- BPMR 7A
- Retail name:
- BPMR7A
- Retail name:
- NGK BPMR 7 A
- Retail name:
- NGK BPMR7A
Sellers list any of these; they are the same part.
About your STIHL FS 450
STIHL line trimmer — Petrol clearing saws. Its spark plug is the BPMR7A spark plug, part BPMR7A.
Other spark plugs the maker lists for this line trimmer: Bosch WSR6F spark plug. STIHL's other approved plug for this model (with NGK BPMR 7 A); gap 0.5 mm.
Where the model number is: The model is on the rating label on the motor housing or the shaft (Ryobi OLT1832, Ozito PXCLTS-018). Take the battery out or switch off before you turn the head over; the old spool's own code is often moulded on it.
Fits these 19 STIHL models
STIHL19 models
FS 120. STIHL's FS 120/250 manual names Bosch WSR 6 F or NGK BPMR 7 A; gap 0.5 mm, replace after 100 operating hours.
FS 250. STIHL's FS 120/250 manual (2016) names NGK BPMR 7 A; gap 0.5 mm, replace after every 100 operating hours.
FS 450. STIHL's FS 300-480 manual names Bosch WSR 6 F, NGK BPMR 7 A or Champion RCJ 6 Y (not all markets); replace after 100 operating hours.
FS 55. STIHL's current FS 55 manual names NGK BPMR 7 A (earlier manuals also Bosch WSR 6 F); gap 0.5 mm, replace after about 100 hours.
FS 561 C-EM. STIHL approves NGK BPMR7A (from STIHL); gap 0.5 mm, replace every 100 hours of operation.
FS 85. STIHL's FS 80/85 manual names Bosch WSR 6 F or NGK BPMR 7 A; gap 0.5 mm, replace after 100 operating hours.
MS 661 C-M. STIHL approves NGK BPMR7A (from STIHL) or Bosch WSR 6 F; gap 0.5 mm, replace after every 100 hours of runtime.
MS 880. STIHL approves NGK BPMR 7 A or Bosch WSR 6 F; gap 0.5 mm, replace after 100 hours.
MS 362 C-M. STIHL's 2017 MS 362 C-M manual (0458-154-8321-A) names Bosch WSR 6 F or NGK BPMR 7 A instead: use the plug your saw's manual names.
FS 38, MS 180. STIHL approves NGK BPMR 7 A, Bosch WSR 6 F or STIHL ZK C 14; gap 0.5 mm, replace after about 100 hours.
MS 271, MS 291. STIHL approves NGK BPMR 7 A, Bosch WSR 6 F or STIHL ZK C14; gap 0.5 mm, replace after about 100 hours.
The other 6 models. STIHL approves NGK BPMR 7 A or Bosch WSR 6 F; gap 0.5 mm, replace after about 100 hours.
Common questions
- Which spark plug fits the STIHL FS 450?
- The STIHL FS 450 takes the NGK BPMR7A spark plug. STIHL's FS 300-480 manual names Bosch WSR 6 F, NGK BPMR 7 A or Champion RCJ 6 Y (not all markets); replace after 100 operating hours.
- Where can I buy the BPMR7A in Australia?
- We track 3 Australian sellers for the BPMR7A; the lowest listed price when we last checked was A$5.60 at Power Mowers. Prices are re-checked daily and dated on this page.
- How do I fit the BPMR7A in a STIHL FS 450?
- 5 steps, listed on this page with the replacement video where the maker has one.
- What happens if I don't change it?
- A worn or fouled plug makes the saw hard to start and run unevenly.
- Is there anything to reset afterwards?
- No reset needed.
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