Hey all. Been working on my nikki carb, everything seems to be in order, have gone through it more times than I can count. Considering a Weber... The issue is now that it starts fine cold, runs well at fast idle, float level correct, but then when I blip the throttle to kick it down, the float bowl immediately fills right up and before very long it is flooding and running rich; black smoke, rough idle, etc. Haven't checked the fuel pressure, but it's a mechanical pump and I see no regulator. Carbs clean as a whistle, gaskets and o-rings good, all vac lines tight. I'm at a loss. Whaddyall think?

 

Does your carb have the sight glass in it? If so what level is it at? Oh and welcome to the forums!! If you could add your car to your signature it will helps us all out in your future posts Thanks!

 

Thanks for the welcome... And, yeah, float level thru sight glass is right in the middle at startup then when kicked down to low idle it rises beyond the top and floods...

 

IIRC this carb has solenoids, 5 of them if I remember from my grandfathers 2200 he had. One controls the mixture, one the choke, one the fuel inlet and the others I am not sure. Is your check engine light on by chance? Try unhooking one solenoid at a time and see if you get the same problem. Grandfather changed his choke one I think and it ran better after that but his was never releasing the choke.

 

Not familar with that particular carb, however if it is flooding out the top if it uses a solenoid valve to control fuel bowl level, then that'd be suspect.

 

OK, will check. Float bowl consistently full now. Really considering Weber conversion. I have to be able to trust this vehicle to take me thousands of miles this winter in other countries... About at wits end on this carb, have had trouble with it and also on the Nissan, both feedback carbs with way too much going in and out. Gas comes from the fuel line and goes straight through the needle valve which ought to be controlled mechanically by the float. Swapped floats and needle valves, wouldn't guess 2 floats to be bad, I think they are solid foam. Thanks for the responses.

 

Ok, hold on. This carb has a needle and seat? To check the float, pull the top of the carb, remove the float. Submerge it in a cup of water, if it floats it is good. If it dosen't it is the problem. Now if it floats what has changed? If the needle and seat are original it could be the needle has a worn out seal (rubber on the bottom).

 

Yeah, finally was able to talk with an old-time mechanic friend of mine. Said to suspect a solenoid,check with ohmeter if resistance above 10, then shot, hows that sound? found a good bit about the nikki carb here
B2200/B2000 OEM Carb Repair
also says on there to possibly suspect O2 sensor, how would I check?

 

Also; Check engine light not on, could it be in limp mode even so?
Without check light, would it give me codes?
Thanks again

 

The issue is with the carb period. Too much fuel in the fuel bowl overflowing according to your post. The O2 sensors are seeing this because it is too rich, carb problem.