20 HP sae j1940 trouble shooting guidance

[coffeesnob]

About a month ago my engine would not idle down when i moved my cable to that position. All linkage and springs etc seemed to be tight and working freely. The engine ran fine other than that. The other day it ran fine (like that described above) then all of a sudden it would barely run and was belching out black smoke while sounding like it was about to conk out but it would still keep running. Its about 7 years old. Ideas and Where do I start to troubleshoot? Thanks

 

[bertsmobile1]

belching out black smoke = very rich running.
Very rich running without missing = flooding carb
So start with the carb, checking that the float is good & the needle valve actually cuts off the fuel supply.
Be carefull when you pull off the float bowl as there is a tiny chance that the main jet may have come loose and is sitting in the bottom of the float bowl.

 

[reynoldston]

Yes running very rich, how is the air cleaner filter and is the choke opening all the way?

 

[coffeesnob]

Yes running very rich, how is the air cleaner filter and is the choke opening all the way?

thanks, all I will check on these. I do know that the airfilter is not clogged.

 

[motoman]

Did any expresso accidentally get into the intake? (joking). Bert did not mention but in the old days on carburetors the float had a "cut off" setting and a droop or full on setting (gas replenishes bowl) . These two settings were (sometimes)set with a little metal tang which could be bent . The ones I remember required holding the float and lid vertically 'til the tang touched the intake needle or a matched a dimension, and then angled for max free fall away from the lid for the droop. We used to check for needle seat wear by looking at the pointy end of the needle and if you could catch a finger nail or even see a wear circle, replace. Also , sometimes floats would puncture , weighing them down so cut off was affected. Shake the float and listen.