Kawasaki fh680v RUNNING RICH!!! Stumped

[dawgslife5436]

Rebuilt Fh680V approximately 300 hours ago. Running great for the last 250. Started to run a little rough at idle (sometimes stall) and now rough at wot. Went to a hotter plug NGK BPR2ES. Didn't work. Plugs are covered with soot after 4 hours of running. New carb, fuel pump, stator, coils. Still having the same issue. Oil seems to turn black with only a few hours of run time. Checked the valve clearances. Perfect. Forgot the mention the heads were completely reconditioned as well. Compression 115 on both. Black smoke from exhaust at when throttling up or engaging the blades. This engine is on a 52" Bobcat zero turn. No idea what to do next. Any help would be greatly appreciated!!!!!!

 

[bertsmobile1]

Black smoke is either rich or timing too far retarded or random missing
Both plugs equally sooty tends to point to the carb or timing key .
Does this engine have the tank vent plumed into the intake manifold ?
If so pull it off & plug the spiggot see if it is pulling fuel vapour from the fuel tank .

 

[Scrubcadet10]

what conditions do you mow in? air filter clear of debris?

 

[slomo]

Make sure the choke is not stuck on all the time. Someone has done some engine work so things have been messed with.

Next check carb needle that is sticking half open or all the way open.

 

[hlw49]

Make sure the choke is not stuck on all the time. Someone has done some engine work so things have been messed with.

Next check carb needle that is sticking half open or all the way open.

Have found several with choke shaft clip broken and the only way to fix it to replace the choke shaft. Unless you get a 25 158 11-S Kohler bushing retainer and drill the choke shaft lever out so it will fit.

 

[dawgslife5436]

thanks for all the responses. Both plugs are equally sooty. Tried cutting today after replacing the plugs. The fouled in less than an hour to the point I couldn't cut anymore. I'm going to pull the cover to see if the flywheel key and flywheel are lined up. I don't know any other way the timing could be off. No tank vent to the manifold. Checked the choke and it works as it should and stays in place when cutting. Took the carb off (OEM carb, 100 hours on it) and it still looked new. Cleaned it and reinstalled. Air cleaner is fairly new. Took it off and ran the engine with no improvement. The choke shaft clip is good. I'm at a loss. I was going to pull the heads today just out of curiosity. I need the mower back up and running by ASAP. Please keep any suggestions coming! Kawasaki FH680v-cs05 23hp

 

[slomo]

Remove the carb. Turn it over. Pressure test the needle and seat at 7psi. Needle should hold 7psi for 30 plus minutes or more.

The below video is on a motorcycle carb. Still has most of the same parts as you have.

New or nearly new parts don't mean much if they don't work.

 

[dawgslife5436]

I did disassemble and clean but I did not pressure test it. I will tomorrow though. I'll post what I find. Thanks for the video.

 

[hlw49]

does it have a smaller fitting than the fuel line fitting next to the fuel line fitting. If so make sure it is open. Some engines have a small hose running from it. Make sure the hose is open.

 

[raisin1]

My symptoms also. I had bad fuel pump that filled crankcase with gas raising level of oil. Oil turned black and soot on plugs.