Kawasaki FC420V ES 15 running rich

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  #1  
Old 09-17-17, 08:55 AM
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Kawasaki FC420V ES 15 running rich

Hi,

I previously was having an issue trying to get my Bunton walkbehind mower to start. Now I can get it to start (yay!), but it runs extremely rich - I can see the fuel pouring through the fuel filter when it runs, and it drains the tank in no time. So it runs like crap - I can make it run with more power by closing the fuel line valve most of the way, but this isn't ideal.

There is white smoke from the exhaust, and after I turn the mower off the smoke continues to pour out of the muffler from the unburned fuel (also sometimes it backfires now).

The float needle valve I noticed was worn, so I replaced this hoping it would solve the problem, but no luck. I think next up I'll try replacing the float itself (it's a plastic float so no tang adjustment to make), but it doesn't seem to be saturated with fuel or anything so I'm not sure that's the issue. I never messed with the carb screw adjustments when I had it off, and it ran great before, so I don't think it's an issue either.

Any thoughts on why it would be sucking so much fuel into the motor?

Thanks,
 
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  #2  
Old 09-17-17, 10:58 AM
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Your needle and seat are failing, remove the carb bowl and turn on the gas as the gas is flowing lift up the float the fuel flow should shut off with minimal pressure, yours won't. Check the oil level it is probably over full and smells like gas, be sure and change it. Have a good one. Geo
 
  #3  
Old 09-17-17, 08:09 PM
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Thanks for the follow up. I already checked the needle valve as you mentioned - it does stop the flow of gas when I push gently against the float with the bowl off.
 
  #4  
Old 09-19-17, 10:47 PM
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Doesn't this have a fuel pump? I'd check the pulse line to see if it's wet... sounds like it might be leaking. Check the oil like Geo says, it probably smells like gas and isn't lubricating well. Change it if so.
 
  #5  
Old 09-20-17, 02:08 PM
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No fuel pump - gravity fed from the tank. was planning to change the oil after I had it up and running for a little bit to warm up the oil, but I can try without warming it up - would this potentially help fix the problem?

Thanks,
 
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Old 09-20-17, 03:23 PM
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Thanks for the follow up. I already checked the needle valve as you mentioned - it does stop the flow of gas when I push gently against the float with the bowl off.
That's not really an accurate test. Bench testing is the only sure method. If you can mount it on the engine on the studs or bolts and leave enough room so that if it does leak it can not get into the intake, or rig up a fuel supply and way to keep the carb level on a bench and see if it leaks. It can take several minutes in some cases before gas may be present.

was planning to change the oil after I had it up and running for a little bit to warm up the oil, but I can try without warming it up - would this potentially help fix the problem?
If you have gas in the oil changing it won't fix the problem but it will prevent another problem caused from running the engine with fuel saturated oil. If you have gas in the oil it should be plenty thin enough to drain without needing to warm it up.
 
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Old 09-20-17, 03:51 PM
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Good points on changing the oil - it does smell like fuel.

I'll look into the bench test - hadn't heard of that before. Thanks!
 
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Old 09-20-17, 04:00 PM
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Check your needle valve and see if it has a spring on it. If so, they call this an anti-bounce spring. It is a wimpy spring and since the bowl is always full, is under constant compression and can get weak. If a bench test shows no leaks yet you still have issues, change the needle valve. Cheap enough it might be a good idea to do anyway.
 
  #9  
Old 09-22-17, 08:48 PM
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Thanks - it's a new needle valve, and yes it does have a spring. Going to try the bench test this weekend.
 
  #10  
Old 05-26-18, 06:10 PM
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https://drive.google.com/open?id=1Ck...lWOKwLoAvVzolOUpdate: bench test was fine. I realized it looks like the main jet is missing. Unfortunately itís an obsolete part, very difficult to find. Should I just try to find one in the same approximate size? Itís part 92063-2257, main jet #100.https://drive.google.com/open?id=1yJ...VtG_MStkIvSWNk
 
  #11  
Old 06-10-18, 07:26 PM
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Problem solved: I ended up getting a replacement jet at a local bike shop that fit - passage size was 102 (vs. 100 OEM), but worked fine.

Thanks,
 
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