Carburetor breakdown and rebuild

The following section covers the steps required to remove breakdown and assembly of a Polaris Sportsman 500 4x4 Year 1998

My neighbor bough a used Polaris Sportsman 500.  I was and still am impressed with it's power,  the power and acceleration was the same as the snow mobiles I used to ride. The tendancy for the front end to lift was much less comfortable.

  Fuel System carburetor aspirated engine. 

Failure Mode: Flood out when trying to accelerate

Special Equipment:  None

Removal Steps (Carburetor)

  1. Turn off the fuel.

  2. Remove the seat and sidle panels.

  3. Remove the breather box and associated hoses.

  4. Loosen the fuel tank and move 2 two inch tubes to provide access to the carburetor.

  5. Remove the bracket holding the rear of the carburetor to the chassis.

  6. Remove the  fuel  lines.

  7. Loosen the front clamp holding the  carburetor to the intake of the engine.

  8. Remove the carburetor then disconnect the choke and accelerator cable

Note: The choke comes out as you loosen the threads as one piece.

Note: For the throttle you need to remove cover plate, 4 screws,  and then remove the cable connected the throttle plate.  After that loosen the treads and remove

Breakdown Steps (Carburetor)

Review the selected pictures:

 

Disassemble the lower half of the carburetor

  1. Remove the lower cover where the float is located.

  2. Remove the drain plug from the cover.

  3. Remove the jets.

     

Disassemble the upper half of the carburetor

  1. Remove the upper cover then the throttle plate with spring. Note: the diaphragm is part of the assembly use care.

  2. Clean all of the ports and passages. I used CRC throttle body cleaner and blew out all of the passage ways.

  3. Set the main jet per the book and adjust the choke the same way.

  4. Reassemble in reverse order.

 

It's important to remember to move slow and easy with the diaphragm and the bowl gasket.  As for this operation it all worked well through the cleaning and I did not have to replace any parts, the ATV was low mileage and I got away with only the repair manual cost and my labor.

This ATV now runs like a scalded cougar. 

 

Conclusion

My neighbor has a good running machine and the only thing I need to do are to change the fluids later this year.