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1958 Corvette: Service Bulletin: Siphon Breaker Plate Unit #7014900 Fuel Injection

Source: Chevrolet Service Bulletin
Bulletin Number: TSB #565, Section VIm
Date: October 14, 1958

Improper seating of leakage past the spill plunger of 1958 Fuel Injection unit, part #7014900, may result in fuel being siphoned from the fuel bowl into one or more cylinders where the inlet valve happens to be open.  The resulting hydrostatic lock can cause bent connecting rods and eventual connecting rod breakage.  The condition occurs when the engine is re-started after being shut off for several hours.  "Stalling" of the starting motor during engine re-starting might be an indication of fuel siphoning into the cylinders.

To overcome this problem, a Siphon Breaker Plate Kit, - part #7017143, has been released for service and is available in limited quantities for installation on #7014900 Fuel Injection units where it is suspected hydrostatic lock problems exist.  Future production #7014900 Fuel Injection units will also incorporate this feature.


Part #:  7017143*

Description:  Siphon Breaker Kit

Kit consists of -

7017314  Siphon Breaker Plate Assembly
7014927  3/16" Diameter Tube Elbow
7014461  Rubber Coupling
7014104  Pump Gasket
7006119  10-32 x 15/16 Screw (4)
7010422  10-32 x 3/4 Screw

* Unpublished number - order through Central Office P & A Dept.


Reference is made to Section V, Manual TP-5, 1958 CHEVROLET CARBURETION AND FUEL INJECTION: -

  1. Remove Gear Pump Drive Cable.
  2. Remove Gear Pump attaching screws and Gear Pump from Fuel Meter.  Discard screws (figure 125).
  3. Remove upper fuel meter mounting bracket (figure 123) and drill a 3/16" hole in the center of the radial portion of the raised area.
  4. Press the short end of 7014927 tube elbow into 3/16" bracket hole (drilled in Step #3) so that 1/4" - 5/16" of the tube protrudes beneath the bracket.
  5. Remove the snap ring and wire screen from the vent on top of fuel meter, and open up a 3/16" hole in the screen directly below the point where tube elbow 7014927 extends beneath bracket (step #4).  NOTE:  The tube must line up with the hole in screen when assembled.
  6. Install screen and snap ring removed in Step #5.
  7. Install mounting bracket removed in Step #3 making sure that tube enters hole in screen.
  8. Install 7014104 Gasket, 7017314 Breaker Plate Assy., 7014104 Gasket and Gear Pump Assy. (removed in Step #2) to the Fuel Pump Assy., in that order, and attach with the five screws furnished in kit.  Note in figure 125 the location of the short, 3/4" screw.  CAUTION:  Make sure all fuel passages are properly lined up.
  9. Install 7014461 rubber coupling between tube on upper portion of breaker plate assembly and tube elbow in upper mounting bracket.
  10. Install gear pump drive cable (removed in Step #1).

Flat Rate Time - .7 hour

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.

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