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This is a motor I rebuilt prev owner ran no oil . New rods ,pistons , crankshaft , fresh honed cylinders , recut valves and seats , all new seals and gaskets , welded the window in the cases , fresh oil and filter . Starts and runs well for a second and then starts to puff black smoke and hunt , recleaned carb , drilled out both welch plugs and ran a strand on electrical wire through everything . Noticed the skinny little tube had serious corrosion/staining on it . New welch plugs installed and reasembled same thing . Ordered a new Kawi carb . While waiting got it hot and did a compression test , 150 both holes , plugs are sooty as expected . , rechecked coil distance at .010 ok . ran motor with neon plug tested on it , no misfires or anything weird . Install new Kawi carb and it runs exactly the same . Cannot be the carb so checked the fuel pump looks like fair flow , started it and run it and used a pair of pliers to pinch fuel line to about 1/2 flow , takes a minute and it cleans up and runs fine . Release the pliers and it goes back to hunting and smoking black . What the heck is going on ? Any ideas ? 40 years at this and never ran across this . Its on a Toro zero turn maybe 10-12 years old . Help

Try running from a spare tank hooked directly to the carb gravity feeding
IF problem goes away then either the fuel pump diaphragm is punchured or the new carb is for a gravity feed system .
IF the pump is fine, try heating & bending the tang for the float so the float closes earlier .

Tried that this morning , gallon test can 12 inches above the carb , starts and run puffs black and hunts same as before . Tank has a knob to shut off fuel so turn it 1/2 off and it starts to get better at 1/4 it runs really nice . Are jets available for these carbs , cannot find a size on the stock jets . Thanks guys .

Check the choke.

So we are making progress,, sort off
has to be in the carb.
Stock jet should be 92063-7037 which is a # 105 size

Have you tried backing out the pilot air jet on the top of the carb
This actually does make a difference to the dynamics of the fuel flow in the main jet

Also double check the timing key because if the key sheared when you were holding & tightening the flywheel that will lead to a retarded spark
I used to check the valve timing & Spark timing by wrapping some masking tape around the flywheel then I came across this app on the web to print out timing tape.
If you print it onto self adheasive paper it will stick to the flywheel but I use plain paper & spray glue
timing tape printer
timing disc printer if you prefer

Red Good said:

used a pair of pliers to pinch fuel line to about 1/2 flow , takes a minute and it cleans up and runs fine . Release the pliers and it goes back to hunting and smoking black .

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Old carb needs to be pressure tested at the needle and seat. New Kawi carb was never tested either.

Red Good said:

gallon test can 12 inches above the carb , starts and run puffs black and hunts same as before . Tank has a knob to shut off fuel so turn it 1/2 off and it starts to get better at 1/4 it runs really nice .

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So stopping down the fuel flow, engine cleans up and runs better. Tells me the needle is sticking open and likes your new 1/4 valve opening to get proper A/F ratio.

hlw49 said:

Check the choke.

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OP states engine runs clean (really nice) at 1/4 valve opening off tank.

hlw49 said:

Check the choke.

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Done , not the problem .Thanks

bertsmobile1 said:

So we are making progress,, sort off
has to be in the carb.
Stock jet should be 92063-7037 which is a # 105 size

Have you tried backing out the pilot air jet on the top of the carb
This actually does make a difference to the dynamics of the fuel flow in the main jet

Also double check the timing key because if the key sheared when you were holding & tightening the flywheel that will lead to a retarded spark
I used to check the valve timing & Spark timing by wrapping some masking tape around the flywheel then I came across this app on the web to print out timing tape.
If you print it onto self adheasive paper it will stick to the flywheel but I use plain paper & spray glue
timing tape printer
timing disc printer if you prefer

Click to expand...

Will check the wheel and key , 3 carbs now all the same ,pilot adjustment in all the way out all the way makes no difference . leads me to beleive its not the carb . Thanks guys .

Pressure test the carb needle yet?

slomo said:

Pressure test the carb needle yet?

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Had a 2 X 2 hole in the side of the block when I got it , patched that and bought a set of rods and pistons and a gasket set . Run it thru the hot tank a couple of times so its clean as its been since it left Kwacker ville .

Pressure test the carb needle yet?

Only really 1thing that cause black smoke from the exhaust , partially burned fuel
So that leaves you with
Excessive fuel coming in
retarded spark
valve timing out

How can valve timing or spark be out when fuel is restricted it cleans up and runs fine . Would those 2 not be affecting it regardless of fuel flow ?

Red Good said:

How can valve timing or spark be out when fuel is restricted it cleans up and runs fine . Would those 2 not be affecting it regardless of fuel flow ?

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Because 98% of most people never adjust valves and hit stumps and log chains in the yard.

Red Good said:

used a pair of pliers to pinch fuel line to about 1/2 flow , takes a minute and it cleans up and runs fine . Release the pliers and it goes back to hunting and smoking black . What the heck is going on ?

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Sounds like excessive fuel entering the bowl. As in the carb needle is not working proper.

You choke down the fuel line and engine smooths out. Great you are on to something. I keep asking if you pressure tested the needle yet. Nothing back from you but crickets......

Or your carb float is not set proper. Allowing too much fuel into the bowl. This condition will cause a rich condition. Something is off.

Take pictures of everything you've worked on. More evidence the more we can help.

The volume of fuel that can be sucked into the engine will vary according to the height of the fuel in the bowl
restricting the fuel supply causes to level in the bowl to drop so less fuel gets into the engine
You get black smoke from a retarded spark because the flame does not have enough time to burn all off the fuel that has entered the cylinder or because the piston has past maximum compression so you get a lazy yellow flame rather than a strong blue one
Petrol burning in a dish has a yellow flame & black smoke .
Similar story with valve timing combustion occurs at less than optimal cylinder pressure so you get a slow yellow sooty flame .

Brand new kawasaki carb , how do you adjust float or needle on a plastic float ?

I doubt that it will be wrong on a genuine brand new carb but you warm the tang gently with a hot air gun & bend it

so you spent around 300 usd for a new carburetor?

200 got a buddy thats a dealer .

slomo said:

Because 98% of most people never adjust valves and hit stumps and log chains in the yard.Fresh rebuild

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Fresh complete rebuilt motor . Rods , pistons , hones , crankshaft , all of it done by
experienced mechanic .

It is unusual for an engine to surge and blow black smoke. Surging is either a lack of sufficient fuel flow or governor adjustment. If you grab the throttle shaft or throttle link or governor arm (whichever can be done safely), can you control the surge? If so, you have a governor/adjustment issue.
The sooty plugs is due to enough fuel but not enough air to properly atomize the fuel.
With all the cheap replacement carburetors I see for sale on eBay, I want to confirm that you bought a genuine Kawasaki replacement? Would you please provide the part number?
FH580V uses an internally vented carburetor, so the issue likely would be the carburetor or the gaskets. Did you replace the insulator gaskets with genuine Kawasaki? Any presence of fuel in the oil?

Yes I did , 200 something to me . Latest , pulled bottom cover off , pushrods out , checked cam timing right on both dots , Measured the cam lobes all the same within a fraction of a mm , anyone know what they should be exactly ? . measured the lifter stools all exactly the same . Pushrods are all the same length. Motor has 125 psi both holes . Pulled the intake to be sure I didn t leave a rag in it as it was apart waiting for gaskets for quite a while , nothing there right to the valves both sides . Checked the governor balls , all correct and in place . What the heck am I missing .

Black smoke is excessive fuel. You already said you pinch down the fuel line and the engine clears up. You were on to something there........

Either your fuel pump is overwhelming the needle or the choke is not adjusted proper. I asked you to pressure test the carb needle, Heard nothing back from you.

Is your choke plate opening ALL the way?

You keep responding with good answers but you still are not cutting grass. Something got missed in this total rebuild.

New parts as in your new OEM carb REQUIRE testing before ruling them out as operational. New doesn't mean new anymore. Your new carb could very well be a Chinese clone. ????

Carb linkages fouled up? You need to follow the Kawi engine manual when adjusting them to a T.

Red Good said:

Yes I did , 200 something to me . Latest , pulled bottom cover off , pushrods out , checked cam timing right on both dots , Measured the cam lobes all the same within a fraction of a mm , anyone know what they should be exactly ? . measured the lifter stools all exactly the same . Pushrods are all the same length. Motor has 125 psi both holes . Pulled the intake to be sure I didn t leave a rag in it as it was apart waiting for gaskets for quite a while , nothing there right to the valves both sides . Checked the governor balls , all correct and in place . What the heck am I missing .

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Your buddy must be getting one heck of a discount as the following what my distributor charges.

With a list of

Kawi box for the kawi part number I ordered from kawi dealer not distributor . Price wont help it run . Does anyone know or have access to the cam lobe specs . All 4 of mine measure right at 30 mm is this correct ? Pushrod stools are good no wear marks at all , pushrods are all the same length and none are bent . ball ends all look perfect no galling anywhere . ?????????????????

When an engine surges and blows black smoke it is because of a fuel to air issue, or timing. Plug the fuel line, or pinch it off and see if the engine speeds up. If it does then it is the float needle leaking or excessive fuel pressure. If it doesn't until it starts to run out of fuel then it is a metering problem. Bad fuel can cause it too. So can a defective ignition system. Where is the "experienced" mechanic who rebuilt it? Why isn't he troubleshooting this problem, instead leaving it in your lap?

I am he . lolololol How does the carb vent the bowl to atmosphere , thru the body or to the intake ?

sgkent said:

When an engine surges and blows black smoke it is because of a fuel to air issue, or timing. Plug the fuel line, or pinch it off and see if the engine speeds up. If it does then it is the float needle leaking or excessive fuel pressure. If it doesn't until it starts to run out of fuel then it is a metering problem. Bad fuel can cause it too. So can a defective ignition system. Where is the "experienced" mechanic who rebuilt it? Why isn't he troubleshooting this problem, instead leaving it in your lap?

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He's not listening to any of us. Concerned about cam bucket length and pushrod ends.

Getting a feeling there are a lot of fisherman out there.

So what is it you think I should do now then ?

Reread your post entirely. There are a few things you might try.

Delete the new carb from your thoughts. Any carb, new or old, will require testing. Any new part will require testing.

pop off with pressure tester is 6 lbs , carb upside down in my hands . What else can you test for beside the float floating ?

take it back to your buddy and let him fix whatever he broke.

Sorry getting a bit frustrated with this thing .

So latest thing ordered 100 and 98 jets from Kawasaki and installed the 98 and still runs rich and hunts with no air filter stuff on it . Got a good set of coils for it and installed them right side up cause Kawi has rotation marked on thier coils , left the kill wires off so it sparks all the time and still runs rich and hunts . Set up like this and turn the key off and the fuel shut off solenoid closes and it runs way better , still not perfect but way better .