Mower bogs down and runs super rich on bumps

[Skippy722]

I’ve got a ~2006’ish Craftsman DGT 6000 lawn tractor with the Kohler 27HP engine. Once it’s warmed up, it seems hitting rougher bumps in the yard causes it to momentarily run super rich, to the point it sometimes blows a nice cloud of black smoke. It could be doing it while it’s cold and I don’t notice because the front yard is simply smoother than the backyard, I’ll test that theory next week.

It has a fresh fuel filter, fires right up, new air filters, fresh spark plugs… I have to creep super slow so it doesn’t bog down (it’ll drop to 1,000rpm according to the tach), but the mowing speed isn’t that fast to begin with. I’ve got a basic understanding of how carbs work, but I’ve been avoiding digging into that, mostly avoiding having to mess with jets…. Should I start there?

 

[samven]

How is its oil consumption. Have you ever had the muffler off to clean the spark arrestor screen. If that gets too clogged up it causes issues that seem like carb problems. If the problem only seems to be at high speed or under load you can try backing the hi speed jet out a 1/4 to 1/2 turn and see if that helps. If the issue seems to be across the hole range it might be the main jet or your float could have a hole in it and be flooded with gas which will cause it to not float properly. That might cause a rich running condition and be even more sensitive to rough riding as the float is heavy and opens more than it should.
Doing a minor carb clean is easy but you should get the bowl and intake gasket and given the age you might want to get the needle and seat and a new float.

 

[danez_yoda]

drop the bowel and check the float. and bowl.

 

[Lubener]

drop the bowel and check the float. and bowl.

Should see a doctor about dropping the bowel.

 

[Lubener]

Check the float for freedom of movement. Sometimes blended fuels will cause the pin which is the hinge for the float to corrode and cause the float to stick.

 

[Skippy722]

Thanks guys, I’ll report back if anything works!