My FH580V on a JD just started running rich and carb is surging. The pilot air adjustment screw makes no change to how the engine runs. It blows out black smoke from the exhaust and plugs get coated with black material. Anyone have an idea what might be going on?
Thanks
Firstly check that the choke is fully dissengaging
Try running without the air cleaner. very fine dust can block off the filter without it looking dirty.
The pilot screw mainly affects the engine at low idle and makes very little difference to top speed
poke some clean white rag down the throat of the carb,
If it comes out wet with fuel then pull the arb apart and check the float and float valve.
Now you said this just "suddenly started to happen" so what happens just before it started to happen ?
Hit a rock/ root & motor stopped ? big backfire ? left out in the rain, snow ? just changed the oil or oil filter ? motor jambed when trying to start it ?
Does the engine feel noticeably down on power ?
What is the FH atttached to ?
There are a lot of things which can make black smoke & rough running.
Air cleaner is removed. Have had the carb apart several times and float seems to be operating normally, along with the choke (opens fully).
Nothing done to mower (John Deere rider) that would have caused the way it's running now
It is definitely getting too much fuel. When plugs are pulled, both are wet and there is raw fuel setting in the intake manifold right behind carb. I have drained gas and replaced with fresh. If fuel line is clamped shut, just before engine runs out of fuel, it smooths out and begins to run as it should.
Either you have a carb problem or the faries put that fuel in the manifold and I would put my money on the carb.
I would also put my money on the float valve not cutting the fuel off.
However you are insisting that the carb is fine so you better get that star dust gun out and stay up all night to blast the faries.:confused2:
Emulson tubes do suffer from errosion but more get wrecked from people shoviing stuff upthere insted of pulling them out to clean them.
Ditto for main jets they do not wear particularly fast .
The float amd float needle does wear both wear and should be considered a tune up item.
AKAIK there are no carb kits for Kawakasi engines .
They have not been in the big engine market for very long and "service kits" seem to be something they have not planned on.
So you will need a float, needle and seat ( if it is replaceable ) and a float bown gasket and while you are there, new manifold gaskes would not go astray.
But before you go buying parts it is usually a good idea to work out what is actually wrong.
SO if you have properly cleaned the float bowl, needle & seat, emulsion tube , idle circuit & bowl vent and it is still flooding the pull off the engine cover and check that the flywheel key is intact.
The 2 halves of the hole should make a perfect square, if not then pull the flywheel and replace the key.
You also need to check the cylinder compressions as a blown head gasket can also cause black fouled plugs.
Oil fouled plugs are wet, sort of shinny and feel greasy to the touch.
Carbon fouled plugs usually look dry and have a fluffy sooty deposit, even if the engine is flooding.
Fun comes when a flooding engine blows head gasket.
Next the valve lash need to be checked.
Kawakasi engines fail by bending and throwing push rods. they are designed to do that rather than blow up completely
Last test is to try and run the engne on one cylinder at a time.
With the carb off you can try a float test with a pressure pump or a spare tank held as high as possible above the carb to get a good head.
A float on a carb with an impule pump should hold 5 to 7 psi. if it has a electric or mechanical pump then it needs to hold 10 to 15 psi.
It helps a lot if you can remember exactly what happened before it started to play up.
It makes a difference when one starts to look.
Fo isntance if you were mowing heavy grass and it just stopped, or hit a rock / root/ branch then it started playing up or it was fine when you stopped mowing last season & just startedd playing up when you went to fire it up for this season.
There is always a reason why someting stops working properly.
I'm now in process of purchasing parts to rebuild carb. Model on engine is FH580V AS04, and parts website starts with FH580V AS06. Called and was told since engine was on a John Deere, parts would not interchange. Sound correct? Quite a price difference between parts warehouse and the Green machine.
Who did you call?
Easiest way is to look at the numbers for instance on the AS04 on repair clinic carb is #15003-7081. Same number at jacks for the AS06.
