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250-C20 CEB-105COMMERCIAL ENGINE BULLETIN OverhauDetroit Diesel AllisonIndianapolis. ndiana 46206

PAGE 1 OF -October 14, 19CECOGASPRODUCERFUELCONTROL, THROTTLESHAFT ASSEMBLY-REWORK

PLANNING INFORMATION:EFFECTIVITY:

REASON:

All of the following gas producer :fuel control assemblies.DDA Part No. CECO Part No.

6889821 104OOOAlO6887770 104OOOA9

To increase the life of the throttle shaft assemb ly seals,thereby eliminating fuel leakage around the throttle shaftassembly.DESCRIPTION: The width of the throttle shaft assembly O-ring groovesis increased to accommodate new O-ring seals with theadditional Teflon back-up rings. Following rework, thefuel control assembly is reidentified.COMPLIANCE: Modification is recommended at first repair or overhaul(whichever occurs first) following parts availability.APPROVAL:MANPOWER:

FAA-DER Approved.It is estimated that approximately one additional manhourwill be required at time of overhaul.

PARTS AVAILABILITY: New CECO P/N Nomenclature &ty101305* Throttle Shaft Assem bly 1101302-012 Packing, Preformed 2MS28774-012 Ring, Back-up 2* P/N 100621 Throttle Shaft Assem blies may be reworkedto P/N 101305 configuration.

INTERCHANGEABILITY:All changes in this bulletin must be accomplishedsimultaneously.

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250-C20 CEB-1058OverhaulPage 2 COMMERCIAL ENGINE BULLETIN

CECOGASPRODUCERFUELCONTROL, THROTTLESHAFT ASSEMBLY-REWORK

TOOLING: NoneWEIGHT AND BALANCE: NoneREFERENCES: DDA (X-1176 and CW-1220CECO PC0 74-90 and PSIL 73-16

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250-C20 CEB-1058OverhaulPage 3COMMERCIAL ENGINE BUL.LETIN

CECO GAS PRODUCER FUEL CONTROL, THROTTLESHAFT ASSEMBLY-REWORK

ACCOMPLISHMENT INSTRUCTIONS:At first repair or overhaul following parts availability, rework P/N 100621 FuelControl Throttle Shafts to accommodate two new P/N 101302-012 Packings withMS 28774-012 Back-up Rings.I.. Disassemb le Fuel Control and Rework Throttle Shaft Assembly.

A. Disassemble fuel control and inspect parts in accordance with 250-C20 Overhaul Manual (Appendix A l).

B. Rework serviceab le P/N 100621 Throttle Shaft Assem bly as follows:1. Increase O-ring groove width by mach ining in accordance withFigure 1.2. Reidentify throttle shaft assembly as P/N 101305 by tagging ormarking part container.

C. If P/N 100621 Throttle Shaft Assem bly cannot be reworked, replacewith P/N 101305 Throttle Shaft Assembly.

II. Reassemble Fuel Control.A. Reassemble fuel control in accordance with 250~C20 Overhaul Manual(Append ix Al) except install two new P/N 101302-012 Packings and twonew MS 28774-012 Back-up Rings on P/N 101305 Throttle Shaft asshown on Figure 2.B. Reidentify the fuel control using l/8-inch number and letter punchesas follows:

Old DDA P/N Old CECO P/N New DDA P/N New CECO P/N6889821 104000AlO 6890904 104000All6887770 104000A9 6891454 104000All-A10

C. Record com pliance with 250 CEB-1058 in the Engine Assem bly (whitepages), M odification Record, Part HI of the Eng ine Log Book.

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250-C20 CEB-1058OverhaulPage 4

COMMERCIAL ENGINE BULLETINCECOGASPRODUCERFUELCONTROL, THROTTLESHAFT ASSEMBLY-REWORK

r BREAK EDGES .002-,015

GROO VE .386-,390 DIA X. 1.149-.159 WIDE -.005-.015RIN BOTTOM CORNERS2 PLACES

REWORK OF THROTTLE SHAFT ASSEMBLYFIGURE 1

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250-C20 CEB-1058OverhaulPage 5 COMMERCIAL ENGINE BUL..LETINCECO GAS PRODUCER FUEL CONTROL, THROTTLESHAFT ASSEMBLY-REWORK

f-

BACK-UP RING-

\

PACKING-

ASSEMBLY OF PACKINGS AND BACK-UP RINGS ON THROTTLE SHAFTFIGURE 2

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250-C20 CEB-1058OverhaulPage 6COMMERCIAL ENGINE BULLETIN

CECOGASPRODUCERFUELCONTROL. THROTTLESHAFT ASSEMBLY-REWORK

MATERIAL INFORMATION:New P/N Qty Nomenclature Old P/N Qty- -6890904 1 Fuel Control Assy, 6889821 1(CECO Gas Producer (CECO104OOOAll) 104000AlO)6891454 1 Fuel Control Assy, 6887770 1(CECO Gas Producer (CECO104000All-AlO) 104000A9)101305 1 Throttle Shaft Assy 100621 1101302-012 2 : Packing, Preformed MS9021-012 2MS28774-012 2 Ring, Back-up ---w-m-

Disposition1

Stock Disposition Notes:1 Rework and reidentify2 Scrap removed part3 Added

L. 0. DavidsonService ManagerAircraft EnginesMJK/bsc

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