Mountfield SP42 Petrol Lawnmower Engine Service Kit For ST120 OHV Engine
We’ve put this kit together so you can get all the correct parts with minimal fuss. The service kit includes:
- A set of genuine Mountfield air filters (inner and outer)
- 1x NGK spark plug
- 600ml of Briggs & Stratton engine oil
This kit is designed to fit Mountfield ST120 OHV engines.
These engines were fitted to the following petrol lawn mower models:
Please pay particular attention to the year of manufacture, as some models may have been fitted with alternative engines outside the years listed. If in doubt, feel free to drop us a message and we’ll be happy to confirm compatibility.
- SP42 (2019–2024)
- S421HP (2019–2020)
- S421PD (2019–2020)
- S421HP R (2019–2024)
- S421PD R (2019–2024)
- S481HP (2017–2020)
- SP46 (2020–2024)
- SP160R (2021–2024)
- SP164 (2019–2024)
- SP185 (2022–2024)
- SP41 (2020–2024)
- SP414 (2020 only)
- SP45 (2017–2022)
- SP454 (2016–2020 only)
- SP51 (2021–2022)
- HP42 (2019–2024)
- HP164 (2019–2024)
- HP185 (2020–2024)
- HP41 (2020–2024)
- HP414 (2020 only)
- HP45 (2020–2022)
- HP454 (2016–2018 only)
- HP46 (2019–2021)
Outdoor Spares Part Number: OSK946945
FAQ
Frequently Asked Questions
Questions we get asked by our customers. If you need more help please get in touch via our chat.
We aim to dispatch all orders within 1 business day. Orders placed before 2pm are usually shipped the same day.
We ship 99% of our orders via Royal Mail. If you select the free shipping option, you will typically receive your parts within 4 working days.
We stock both genuine parts and premium aftermarket alternatives under our own brand, HardRidge Parts, designed for durability and performance.
Each product page includes compatibility information. If you’re unsure, just contact us with your model number—we’re happy to help.
Look for a sticker on the lawnmower deck—it will show the model year and often an ART number. We can identify your machine using that information.
We offer a 30-day return policy. Parts must be unused and in their original condition. Please see our Returns Policy page for full details.
At the moment, we only ship within the UK.
Orders under £30 are sent via Royal Mail 2D tracking, which provides delivery confirmation but not live updates. Orders over £30 are sent with a fully tracked service via Royal Mail or Evri.
You can email us atsales@outdoorspares.comor use the contact form on our Contact Us page. We typically respond within 24 hours on business days. We also offer live chat and usually reply straight away, though during busy periods it may take a little longer.