Archived from the Tools In Action forum (Makita). This thread is read-only.
The engine starts well and runs when choke s on. After warm up 3/4 minutes press throttle it cuts out straight away. Cleaned spark plug and drained oil put fresh in . Was not used for about six months prior to this. Blades are working but slow but intermittently will power up. Have noticed air bubbles in fuel pipe, could this have something to do with it? Any suggestions welcome. They are in new condition not knackered
It sounds like your engine is dealing with a classic fuel delivery or air-fuel mixture issue. Especially common after sitting unused for several months. If it only runs with the choke on and stalls when you throttle up, it’s likely not getting enough fuel (running too lean). The presence of air bubbles in the fuel line is definitely a red flag. This can indicate an air leak somewhere in the fuel system, like a loose fuel line connection, a cracked fuel line, or even a failing primer bulb. Air getting into the system disrupts proper fuel flow, which could explain the weak or inconsistent blade power too.
Since you’ve already refreshed the oil and cleaned the spark plug (good moves), next check the fuel lines for any cracks or loose fittings. Replacing old fuel lines is a cheap fix and often solves this issue. Also, consider cleaning the carburetor or at least the jets, gummed-up fuel can clog those tiny passages easily after sitting.
If the blades are slow but occasionally power up, it may also point to inconsistent combustion—again tying back to fuel/air mix problems.
A carburetor rebuild kit and fresh fuel lines usually do wonders. Let me know how it goes!