Symptoms
- Cord takes much more effort than it used to
- Feels like pulling against strong resistance the whole way
- Started easily last season
- Engine may or may not eventually start
Likely causes
- CommonOld or too-thick oilUsing the wrong oil grade, or oil that's overdue for a change, increases internal drag.
- CommonGrass buildup under the deckCompacted clippings can drag on the blade, making the engine harder to turn.
- PossibleWorn compression release mechanismSmall engines use a compression release to ease starting; if it fails, pulling gets much harder.
- PossibleBent blade or blade hitting the deckA bent blade can rub against the mower deck, adding resistance to every rotation.
What to do
- Disconnect the spark plug wire, then tip the mower and scrape out any packed grass clippings from under the deck.
- Spin the blade by hand (with plug wire off) to check for rubbing or an obvious bend.
- Check the oil level and condition; change it if it's overdue or the wrong grade for the season.
- Reinstall the spark plug wire and try pulling again to compare effort.
- If it's still very hard to pull with a clean deck and good oil, the engine's compression release may be worn and need service.
- Consider a professional tune-up if resistance remains high, since internal engine wear can also cause this.
Tools and parts
- Putty knife or scraper
- Spark plug socket
Small engine oilSearch: “lawn mower engine oil”
When to call a pro
A small engine mechanic can test the compression release valve and overall compression if cleaning and an oil change don't help.
Safety
Use caution
Always disconnect the spark plug before reaching under the deck or spinning the blade by hand.