Generac carburetor cleaning, runs rich

[dart451]

I'm working on a Generac 4000XL generator w/generac GN-220, 7.8hp engine. Motor sitting for over a year, carb very dirty inside and out. Cleaned out tank, new fuel line, put in in-line fuel filter, removed carb, disassembled, cleaned with ultrasonic cleaner, cleaned it really nice! Engine starts easy but is running rich, no adjustments on carb. choke is fully open. I took carb off again and decided to try another ultrasonic cleaning. Before this, I ran some of my narrow welding cleaning wires through the orifices as best I could. Any of the Master small engine mechanics think of anything else I can try? I also by-passed the tank with a portable fuel tank to rule out the tank....also tried a new plug properly gapped. Ultrasonic is still running...

[smallen]

running rich is not caused by blockage, may have lost the small rubber plug (1/8") from bottom of carb,held in place by bowl, next to bowl screw.
pressure test needle/seat,check float for leak

[dart451]

wouldn't I have found the rubber plug in the bottom of the bowl when I took it off? Also, how do you pressure test the needle/seat?

[smallen]

if you where looking for it when you removed bowl, look to see if it still in there, use hand pump with carb upside down, wet needle with fuel, pump to 4-5 psi, should hold , check float for fuel inside

[dart451]

here is a pic of the carb...


Ok, I pressure tested it...holding it upside down, it takes over a minute for the 5lb pressure to dissipate. With carb right side up, it takes about 5 seconds to zero out.

[dart451]

I found this on this particular Generac 4000XL generator:

The black smoke from exhaust is engine running rich, so its a fuel delivery. Observe the main jet inside the fuel bowl. If it was drilled out this would explain it running rich. Also if its a Nikki carb there should be a rubber stopper in the idle circuit next to the main jet. If this is missing this may explain the engine running rich if the main jet is not compromised. Change out the spark plug after you address the carb issues

Needless to say, it is a Nikki carburetor so I guess there is supposed to be a black plug in the idle circuit! Thank you smallen for bringing that plug to my attention! You know, before I even started working on this thing, I checked the spark plug and it was already black from running rich (new plug)so...I guess someone messed with the carb at one time and lost the plug!

[smallen]

needle is leaking, should hold for 5 min, clean needle and seat with q-tip, test again, get the needle to hold before you worry about plug, generac dosnt offer this plug, briggs did use this type carb on some of the vanguard engines, may be able to check there, new carb is about 60.00

[dart451]

Ok, I already found the plug and ordered it...I will play with the need and seat a bit to see if I can get it to seal better. It seems in pretty good shape...the needle has the rubber tip and the seat is brass it appears...q-tip it is!

Alrighty then! I went and checked the needle and seat again and it still leaked...then I checked my hand pump while blocking the end of the hose with my finger...still leaked! Leaking hose! Shit! Now after getting a good hose that would hold pressure while manually blocking it, I checked it again...now the needle and seat no longer leaks! Guess you have to check your testing tools once in awhile!? ROFL