520H surging issues

[rhondamack 1]

Hello,

I have a 520H and it suddenly started surging this week when I started it up. I cleaned the carburetor, but it’s still surging. The gas is fresh, and I’ve already replaced the fuel pump, air filter, and fuel filter. Does anyone have ideas on what might be causing this or what I should troubleshoot next? I’m on over 9 acres, and a good portion is grass—push mowing just isn’t realistic because it takes way too long.

[sqrlgtr 2,926]

My 520H manifold was leaking at the seam where it goes together, they are a 2 piece design and known for leaking. 

[JoeM 9,927]

I have had to clean those up to three times, make sure you clean the main jet.

 

Edited 4 hours ago by JoeM

[JoeM 9,927]

2 minutes ago, sqrlgtr said:

My 520H manifold was leaking at the seam

Along the same lines I have seen the bolts loose and just need tightened. You can spray carb clean around the manifold while running to see if it revs. The plugs will tell a story too. 

[Ed Kennell 46,074]

46 minutes ago, JoeM said:

I have had to clean those up to three times, make sure you clean the main jet.

 

 

 

               Mine got a little better every time I cleaned it.    It took three cleanings  to finally stop the surging.

[lynnmor 8,827]

1 hour ago, JoeM said:

 

 

 

 

Just above the IDLE ADJUSTMENT NEEDLE is a welsh plug, shown but not identified in the above drawing.  Make sure it didn't fall out.