Kohler k582 runs poorly at operating speed. ok at idle. ambient temperature is 30 degrees.carb main fuel needle adjustment is ineffective. backfires with occasional black smoke. condition started as intermittent and now is persistant. new fuel filter. fresh full tank of gas. plugs, points, wires,condenser,coil, and fuel pumps have been replaced w/in the last 150 machine hours. this engine runs a truck mounted carpet cleaning plant.

check the flywheel key to be sure it is still in position if that is ok i would check valves to be sure they are in spec.

On some float-type carburetors, you can adjust the air-fuel mixture and engine speed at idle. Check for an idle speed screw designed to keep the throttle plate from closing completely, and an idle mixture screw that limits the flow of fuel at idle. If your carburetor contains these screws, proceed below.

1. With the engine off, remove the air filter and air cartridge.
2. Locate the idle mixture screw and turn it clockwise until the needle lightly touches the seat. Then, turn the screw counterclockwise 1-1/2 turns.
3. If your carburetor has a main jet adjustment screw at the base of the float bowl, turn the screw clockwise until you feel it just touch the seat inside the emulsion tube. Then, turn the screw counterclockwise 1 to 1-1/2 turns. Replace the air cleaner assembly and start the engine for final carburetor adjustments.
4. Run the engine for five minutes at half throttle to bring it to its operating temperature. Then, turn the idle mixture screw slowly clockwise until the engine begins to slow. Turn the screw in the opposite direction until the engine again begins to slow . Finally, turn the screw back to the midpoint.
5. Using a tachometer to gauge engine speed , set the idle speed screw to bring the engine to 1750 RPM for aluminum-cylinder engine or 1200 RPM for engine with a cast-iron cylinder sleeve.
6. With the engine running at idle , hold the throttle lever against the idle speed screw to bring the engine speed to "true idle." Then, repeat the idle mixture screw adjustments from Step 4 to fine-tune the mixture .

I had this puzzler too! Turned out the problem is caused by the fuel-bowl needle valve. It may look OK but looks are deceiving. It gets a coating on the tip that causes a poor seal ... poor enough to allow fuel to flood the engine after a short run time. The flooded engine dies, but restarts OK after a delay that clears (cooks off) the excess fuel that flooded/killed the engine. SOLUTION: Remove the needle valve and carefully wipe and clean the tip with a white cloth soaked in solvent (gas is OK). The cloth will show the deposits that cause the problem. Carefully re-install the needle valve and float parts, start the engine, confirm that it runs OK and continuously. Simple fix .... puzzling problem.

That sounds like either bad (old) gasoline or the carburetor needs cleaning very badly - it's running very lean.

Instructions

1. • 1 Park your RSV 1000R on a well-ventilated, level area, using its kickstand.
     
   • 2 Start the engine and let it idle in place until the temperature gauge built into the instrument cluster indicates a minimum internal temperature of 180 degrees Fahrenheit. This is the motorcycle's ideal operating temperature.
     
   • 3 Take note of the engine idle speed, using the tachometer needle, while the engine is running. Ideally, the engine should idle steadily at 1,250 rpm.
     
   • 4 Adjust the engine idle speed to 1,250 rpm, using the idle adjuster screw hidden between the lower right edge of the fuel tank and the upper edge of the right middle fairing panel. Turn the idle adjuster screw clockwise to increase the engine idle speed, or counterclockwise to decrease the engine idle speed, using a small flat screwdriver if your RSV 1000R's frame (VIN number) precedes ZD4MEE009YS000292. A plastic knob allows the engine idle speed to adjusted by hand on RSV 1000R models with a frame (VIN) numbers starting from ZD4MEE009YS000293.
     
   • 5 Rev the engine two to three times and observe the tachometer. The engine should return to a 1,250 rpm idle. Adjust the engine idle speed as needed, using the method described, then rev the engine again. Problems may exist within the throttle control, fuel-injection system or engine, if the engine idle speed will not hold steady at 1,250 rpm. Contact your local Aprilia service facility for assistance.
     
   • 6 Stop the engine, once you have obtained a steady 1,250 rpm idle speed.
     

Instructions

1. • 1 Park your RSV 1000R on a well-ventilated, level area, using its kickstand.
     
   • 2 Start the engine and let it idle in place until the temperature gauge built into the instrument cluster indicates a minimum internal temperature of 180 degrees Fahrenheit. This is the motorcycle's ideal operating temperature.
     
   • 3 Take note of the engine idle speed, using the tachometer needle, while the engine is running. Ideally, the engine should idle steadily at 1,250 rpm.
     
   • 4 Adjust the engine idle speed to 1,250 rpm, using the idle adjuster screw hidden between the lower right edge of the fuel tank and the upper edge of the right middle fairing panel. Turn the idle adjuster screw clockwise to increase the engine idle speed, or counterclockwise to decrease the engine idle speed, using a small flat screwdriver if your RSV 1000R's frame (VIN number) precedes ZD4MEE009YS000292. A plastic knob allows the engine idle speed to adjusted by hand on RSV 1000R models with a frame (VIN) numbers starting from ZD4MEE009YS000293.
     
   • 5 Rev the engine two to three times and observe the tachometer. The engine should return to a 1,250 rpm idle. Adjust the engine idle speed as needed, using the method described, then rev the engine again. Problems may exist within the throttle control, fuel-injection system or engine, if the engine idle speed will not hold steady at 1,250 rpm. Contact your local Aprilia service facility for assistance.
     
   • 6 Stop the engine, once you have obtained a steady 1,250 rpm idle speed.
     

hi there harryandmeli
sounds like you still have a restriction in your carb or the float level is not right
check all the opening s and jets carefully, particularly main jet and emulsion tube air bleeds
and the idle air bleed , and idle jet, is the tank clean and no water ? , is the tank breather working ?, make sure gaskets at carb flange are ok - no leaking of air , make sure air filter is not blocked ?

provided compression and spark ok,( spark should jump a 6 mm gap minimum ) to pass a coil test and fuel flow from tank to carb is good , these engines have hydraulic valve lifters and like 10w/30 kohler oil , everything being = engine should run good

remember F A C T S

F = Fuel , A = Air , C = Compression , T = Timming , S = Spark

take a look

cheers hope it helps

pauly46

carb problem or vacuum leak at carb base gasket or intake manifold

is ther e no fuel mixture screw u can try adjusting

Try changing the spark plug.