Can someone give me some advice toward fixing this issue with my Hyundai Mower.
I dont know the specific engine name or type, but I own the HYM430ST-SP. It was running extremely slow so I went to a local shop(now closed). They explained that the tension spring had rusted and rhat it needed replaced(£10 labour included). I am aware of how to fix it, but wanted it done properly and professionally.
It worked fine for a couple of months but now won't stop surging. The revs are jumping between 3700-4200 constanlty and the tension spring it bumbing back and forth. I decided to try and fix this issue myswlf with little improvement.
I was told to dump it onto its side and pull a few time but have refused because I dont want fuel or oil flooding any parts of the engine. Can someone please give me proper advice on how to stop it surging.
Rather than type it all out myself, these are the general causes of surging and hunting (which is what it sounds like your mower is doing) as copy pasted from google.
Common Causes and Solutions Blocked Carburetor Jet: The most common cause is a clogged carburetor, particularly the tiny pilot jet restricting fuel flow. Clean the carburetor, specifically the bowl nut and its jet, which are often to blame. Stale Fuel or Water: Fuel that has sat for too long can cause blockage, or water in the fuel tank can create erratic running. Failed Diaphragm: On some engines (especially older Briggs & Stratton), the carburetor diaphragm can harden or rip, causing air leaks and poor fuel flow. Air Leaks: A faulty or torn gasket between the carburetor and the engine intake can allow too much air, forcing the engine to hunt for a consistent RPM. Governor Spring Issue: A worn, damaged, or stretched carburetor spring can cause the governor to fail to stabilize the engine speed.
In my experience it usually either a dirty carb or a faulty or misconfigured spring (either throttle or governor).
This guy does some good videos on fixing mower issues.
If the above video doesn't help, look through his other videos you might find something useful.
