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RESERVOIR-VACUUM DESCRIPTION The vacuum reservoir is a plastic storage tank connected to an engine vacuum source by vacuum lines. A vacuum OPERATION The vacuum reservoir is used to supply the vacuum needed to maintain proper speed control operation when DIAGNOSIS AND TESTING VACUUM RESERVOIR 1. Disconnect vacuum hose at speed control servo and install a vacuum gauge into the disconnected hose. 2. Start engine and observe gauge at idle. Vacuum gauge should read at least ten inches of mercury. 3. If vacuum is less than ten inches of mercury, determine source of leak. Check vacuum line to engine for leaks. Also check actual engine intake manifold vacuum. If manifold vacuum does not meet this requirement, check for 4. If vacuum line to engine is not leaking, check for leak at vacuum reservoir. To locate and gain access to reser- voir, refer to Vacuum Reservoir Removal/Installation in this group. Disconnect vacuum line at reservoir and con- 5. Verify operation of one-way check valve and check it for leaks. Certain models may be equipped with 2 check-valves. a. Locate one-way check valve. The valve is located in vacuum line between vacuum reservoir and engine vacuum source. Disconnect vacuum hoses (lines) at each end of valve. b. Connect a hand-operated vacuum pump to reservoir end of check valve. Apply vacuum. Vacuum should not bleed off. If vacuum is being lost, replace one-way check valve. c. Connect a hand-operated vacuum pump to vacuum source end of check valve. Apply vacuum. Vacuum should flow through valve. If vacuum is not flowing, replace one-way check valve. Seal the fitting at opposite 8P - 10 SPEED CONTROL DR/DH |