Small Gas Engine: Carburetor - II

Supplement for CEV #887

Small Gas Engine: Carburetor - II

Supplement for CEV #887

Goal:

The student follows the procedures necessary for the maintenance, disassembly, and assembly of Pulsa-Jet Carburetors.

Objectives:

1.to learn the appropriate techniques used to disassemble and assemble a

Pulsa-Jet Carburetor for horizontally shafted engines

2.to understand the correct steps needed to disassemble and assemble a

Pulsa-Jet carburetor for vertically shafted engines

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Small Gas Engine: Carburetor – II

Quiz I

True or False

____1. The Pulsa-Jet has two fuel pickup tubes.

____2. The diaphragm serves as a fuel pump.

____3. The throttle butterfly is difficult to replace, due to its location within the carburetor itself.

____4. A screwdriver is used to remove the seat underneath the needle valve.

Short Answer

5. If the long pickup tube enters the main fuel tank, where does the short pickup tube enter?

6. When replacing the diaphragm, where should the spring and cup washer be placed?

Small Gas Engine: Carburetor - II

]Quiz II

True or False

____1. The Pulsa-Jet carburetor for vertically shafted engines has an automatic

choke.

____2. It is acceptable to replace the needle valve without replacing the seat.

____3. The automatic choke should be tripped before attaching the choke linkage cover.

Multiple Choice

____4. What is used to repair a warped fuel tank?

  1. repair kit with Teflon washer and roll pin
  2. warped tanks must be replaced
  3. fuel tanks do not warp

Short Answer

5. Why should the O-rings be replaced?

6. How can one detect a warped fuel tank?

7. When replacing the diaphragm, should the spring and cup washer be placed in the top of the fuel tank?

8. What is the washer from the fuel tank repair kit made of?

Small Gas Engine: Carburetor - II

Final Quiz

True or False

____1. The cup washer protects the diaphragm from the sharp end of the spring.

____2. When replacing the diaphragm on a Pulsa-Jet for vertically shafted engines, the spring should be placed inside the carburetor.

____3. If the needle valve is replaced, the seat should be replaced as well.

____4. A Pulsa-Jet carburetor for vertically shafted engines must be turned upside down for removal from the fuel tank.

Multiple Choice

____5. What is used to check a fuel tank for warping?

  1. straight edge
  2. tape measure
  3. .002” thickness gauge
  4. both a and c are used

____6. What parts are included in the needle valve repair kit?

  1. washer
  2. needle valve
  3. seat
  4. all of the above

Short Answer

7. What should be done to the needle valve before installing it?

8. What does the throttle butterfly attach to?

9. On a Pulsa-Jet for vertically shafted engines, what should be done before tightening the carburetor mounting screws?

10. What is the purpose of the well within the fuel tank?

Small Gas Engine: Carburetor – II

Answer Key for CEV #887

Quiz I

True or False

T1. The Pulsa-Jet has two fuel pickup tubes.

T2. The diaphragm serves as a fuel pump.

T3. The throttle butterfly is difficult to replace, due to its location within the

carburetor itself.

F4. A screwdriver is used to remove the seat underneath the needle valve.

Remove the seat with a carburetor nozzle tool. A screwdriver can score the threads or damage the seat.

Short Answer

5. If the long pickup tube enters the main fuel tank, where does the short pickup

tube enter?

A fuel well within the tank where fuel stays at a constant level.

6. When replacing the diaphragm, where should the spring and cup washer be

placed?

The spring and cup washer should be underneath the diaphragm

Small Gas Engine: Carburetor - II

Answer Key for CEV #887

Quiz II

True or False

T1. The Pulsa-Jet carburetor for vertically shafted engines has an automatic choke.

F2. It is acceptable to replace the needle valve without replacing the seat.

Always replace all parts—seat, washer, and needle valve—at the same

time.

T3. The automatic choke should be tripped before attaching the choke linkage

cover.

Multiple Choice

a4. What is used to repair a warped fuel tank?

  1. repair kit with Teflon washer and roll pin
  2. warped tanks must be replaced
  3. fuel tanks do not warp

Short Answer

5. Why should the O-rings be replaced?

They are inexpensive and vital to maintaining a good seal.

6. How can one detect a warped fuel tank?

measuring with a straight edge and thickness gauge

7. When replacing the diaphragm, should the spring and cup washer be placed

in the top of the fuel tank ?

No, they should be installed in the carburetor and the diaphragm placed on top of the cup washer.

8. What is the washer from the fuel tank repair kit made of?

Teflon

Small Gas Engine: Carburetor - II

Answer Key for CEV #887

Final Quiz

True or False

T1. The cup washer protects the diaphragm from the sharp end of the spring.

F2. When replacing the diaphragm on a Pulsa-Jet for vertically shafted engines, the spring should be placed inside the carburetor.

T3. If the needle valve is replaced, the seat should be replaced as well.

T4. A Pulsa-Jet carburetor for vertically shafted engines must be turned upside down for removal from the fuel tank.

Multiple Choice

d5. What is used to check a fuel tank for warping ?

  1. straight edge
  2. tape measure
  3. .002” thickness gauge
  4. both a and c are used

d6. What parts are included in the needle valve repair kit ?

  1. washer
  2. needle valve
  3. seat
  4. all of the above

Short Answer

7. What should be done to the needle valve before installing it ?

turned out to prevent damage

8. What does the throttle butterfly attach to ?

the throttle shaft

9. On a Pulsa-Jet for vertically shafted engines, what should be done before

tightening the carburetor mounting screws.

Load the choke.

10. What is the purpose of the well within the fuel tank ?

It maintains a constant level fuel supply for the carburetor.

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Small Gas Engine: Carburetor - II

Supplement for CEV #887

Small Gas Engine: Carburetor - II is the second in a two-part series featuring the identification of parts, disassembly, repair and reassembly of the Briggs and Stratton horizontal Pulsa-Jet and vertical Pulsa-Jet carburetors. Dr. David Lawver, Associate Professor of Agricultural Education and Communications at TexasTechUniversity, demonstrates the proper procedures for removing and replacing the diaphragm, needle valve assembly and throttle shaft. Checking the fuel tank for warping is also demonstrated.

Enhanced Learning! This production incorporates CEV’s VideoActive format, which has been designed to create an interactive learning environment by incorporating questions and discussion into each program. Color and numeric coding for each section make selection of a desired topic or review of specific information much easier and faster.

Following each section, a short quiz will be presented. A comprehensive ten question final quiz will be presented at the end of each part. Included in this teaching guide are corresponding copy-ready student quizzes, a teacher’s key, an outline for performing the procedures demonstrated in this production and additional information sheets regarding each Pulsa-Jet carburetor.

Easy-to-use Format: This teaching guide is designed to follow the material as it is presented in the presentation. The enclosed outline briefly describes the procedures performed. Next to each procedure, remarks concerning the tools that are used to complete the procedure and any special instructions are listed. This format enables the viewer to follow along with the production and it serves as a guide when performing the procedures after viewing.

Small Gas Engine: Carburetor - II

Tools and equipment needed: flat blade screwdriver, 1/2” combination wrench, carburetor nozzle tool, mixture adjustment screwdriver, long nose pliers, holding screwdriver, straight edge (small square), thickness gauge

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Procedure Remarks

PULSA-JET CARBURETOR FOR

HORIZONTALLY SHAFTED ENGINES

Remove diaphragm coverUse flat blade screwdriver

Replace diaphragmCup washer should cover the spring and be placed below the diaphragm; align and install new diaphragm

Replace diaphragm coverUse flat blade screwdriver; tighten using an alternating sequence

Remove needle valveUse 1/2” combination wrench

Remove needle valve seatUse carburetor nozzle tool

Install new needle valve repair kitUse carburetor nozzle tool; turn needle valve out before installing; use 1/2” combination wrench

Adjust needle valveAfter seating needle valve, turn it out 1 1/2 turns using a mixture adjustment screwdriver; do not over tighten when seating

Inspect throttle shaftMove side to side and check for slack

Remove throttle shaftRemove spiral in throat of carburetor; use small flat blade screwdriver and remove throttle butterfly; lift throttle shaft out

Install new throttle shaft Reuse fiber washer from old throttle shaft; insert throttle shaft into carburetor; use a holding screwdriver to start screw when installing throttle butterfly; insert spiral into carburetor throat

Tools and equipment needed: flat blade screwdriver, 1/2” combination wrench, carburetor nozzle tool, mixture adjustment screwdriver, long nose pliers, holding screwdriver, straight edge (small square), thickness gauge

Procedure Remarks

PULSA-JET CARBURETOR FOR

VERTICALLY SHAFTED ENGINES

Remove choke linkage coverUse flat blade screwdriver

Disconnect choke linkagePull linkage out of choke arm assembly

Remove carburetor from fuel tankRemove screws using flat blade screwdriver; note special screws used to attach carburetor to fuel tank; with fuel tank empty, turn carburetor and tank upside down and carefully lift tank off of carburetor

Check fuel tank for warpingFuel tank must be level; use a straight edge and .002” thickness gauge

Remove diaphragm Replace if torn or excessively worn

Remove needle valveUse 1/2” combination wrench

Remove seatUse carburetor nozzle tool

Install new needle valve repair kitUse carburetor nozzle tool; turn needle valve out before installing; use 1/2” combination wrench

Adjust needle valveAfter seating needle valve, turn it out 1 1/2 turns using a mixture adjustment screwdriver; do not over tighten when seating

Install diaphragmInstall spring and cup washer into carburetor; install spring in kit on new diaphragm

Replace carburetor on fuel tankUse roll pin and Teflon washer from repair

kit if fuel tank is warped; turn carburetor upside down and align fuel pickup tubes, diaphragm spring and roll pin; replace all screws but do not tighten

Load the choke Move the choke butterfly to an over center position and reattach linkage to choke arm assembly; tighten carburetor screws in a staggered sequence

Replace choke linkage coverTrip the choke so the choke butterfly is fully closed; replace cover and gasket; use flat blade screwdriver

Replace O-ring Install new O-ring in groove in throttle bore

Inspect throttle shaftMove side to side and check for slack; replace if necessary

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