When engine runs, it surges in low and high rpm. We cleaned the carburetor, the fuel filter and set the valves. It starts up very easily but still surges a little and appears to be running lean. I do not want to cut the lawn for fear of running it hot and causing an overheat. Thank you for your help. MaryAnn and Frank
By cleaning the carb do you mean pulling it off completely removing all the jets and chacking all of the fine holes for blockages ?
If that answer is yes then get some WD 40 or similar IN A TRIGGER PACK ( yes I was shouting ) and spray around the carb when the engine is running paying particular attention to the inlet manifold.
If you get a sudden change then air is leaking in at that point and you need to replace whatever is there ( gasket O ring etc).
Thank you for your answer --- I did not use WD40, but used AMSOIL MP which is very similar and did not have any change in operation. I will try it again with the WD40,
We did strip down the complete carburetor and cleaned out all the passages and jets. Appreciate your info and will get back with you. thanks again
No need to try again, any fluid will do, all you are trying to do is let it get sucked into the engine i there is an air leak in there which is why you were told to spray it around the carb/ engine joint.
Trigger pack is important to get a flood of fluid there and to prevent the propellant found in spray packs catching fire. Some even use water but that becomes messy if too much gets sucked into the engine.
Hunting is running lean and running lean is either not enough fuel or too much air entering after the carb had dispensed the fuel.
Not enough fuel is either not enough flow to the carb
or float height too low
Or fuel jets blocked
So it is back to the beginning & try again.
you can slowly cup your hand over the top of carb while running at idle. If the idle increase and the engine smooths out then theres a vacumm leak.
Suspicion of lean running... did you look at the porcelin color on the plugs? Perhaps the condition has not persisted long enough to burn off the normal tan to a whitish or lighter color. Check. It could be another clue. Also did power trail off a little which would be expected under load such as hills, PTO on, baskets full ?