John Deere bogging down

[Braindrain]

Few weeks back, I was using my Dad's John Deere to mulch some damp leaves when it started bogging down and puffing black smoke now and then. Eventually, it just wouldn't stay running, and the plugs were black but dry. It's been well maintained, so I plan to check valve lash, replace old fuel lines, and probably drop in a new carb, are there any other tips I can do?

 

[greenmachineguy761]

Black dry plugs and bogging sounds like it's drowning in fuel. Also, make sure to check the air filter and see if the carb float or needle valve might be sticking. Good luck

 

[DirtDozer]

Few weeks back, I was using my Dad's John Deere to mulch some damp leaves when it started bogging down and puffing black smoke now and then. Eventually, it just wouldn't stay running, and the plugs were black but dry. It's been well maintained, so I plan to check valve lash, replace old fuel lines, and probably drop in a new carb, are there any other tips I can do?

I agree with @greenmachineguy761. It seems to be a combustion issue and the black smoke indicates it's getting too much fuel. A clogged filter will starve the engine of air and cause a rich condition so I'd also check the air filter first. Since it's mulching leaves, it's probably sucked up a ton of dust and debris. Also check if the choke plate might not be opening all the way, especially if the linkage is gummed up. This would also keep it running rich all the time. If you're going to replace the carb, it might be worth cleaning the one you have first. Sometimes all it takes is a good cleaning and a new gasket to get them running right again. No sense in replacing a good carb if you don't have to.

 

[nubl3d]

I think you should replace the air filter and make sure the choke isn't sticking, then there's fuel contamination too, you gotta check that out

 

[timtomtams]

I agree with them! Don't forget to ensure that the ignition timing and coil output are solid. The unburned fuel that shows up as black smoke is a cause of a weak spark.