Vacuum & Fuel Pressure Tester

Vacuum & Fuel pressure tester

Locates leaks in gasoline, sticky valves, weak valve springs, burnt valve and fuel pump pressure.

Suits majority of plug types

Made in Taiwan

OPERATING INSTRUCTIONS

Vacuum Test

Connect vacuum hose as close to Intake manifold as possible. On V type engines having two manifolds, make separate tests on each manifold. Start engine and adjust throttle butterfly valve. Set Idling adjustment on Carburettor, so that engine idles smoothly. If engine is in good condition, vacuum gauge pointer will remain steady at a reading between 18 and 21

Note Vacuum readings will vary according to altitude in different locales.

All normal engines should show a vacuum reading between 18 to 21 Inches.

Sticky Valves

With engine at Idling speed. Intermittent dropping bock of pointer, about four divisions indicates sticky valves. If injection of penetrating oil into intake manifold sufficient to reach valves temporarily stops pointer from dropping bock, you can be certain the valves are sticking.

Weak Valve Springs

If valves seal properly at Idling speed, vacuum gauge should remain steady between 18 to 21 or have a very slight fluctuation. If pointer fluctuates rapidly at higher engine speeds, this is an indication of weak valve springs

Burnt Valve

Whenever a burnt valve comes into operation, vacuum gauge pointer will have a constant drop. This action can also be caused by insufficient tappet clearance holding valve partly open or a spark plug occasionally missing

Valve Timing

With engine at idling speed, a low steady reading of the vacuum gauge Indicates late timing or an intake manifold leak. Usually a condition of late timing gives a gauge reading of 12 to 15. If this reading of the vacuum gauge is encountered, it must be remembered that leaks and poor compression can also result in a low vacuum reading. Also if the ignition timing is off, the vacuum reading will be low.

Vacuum Pump Test

Connect the vacuum gauge hose to the vacuum where the wind shield wiper is connected. The vacuum reading should be 18 to 21 at Idling speed. When the engine is suddenly speeded up, the vacuum should not suddenly drop to zero. A low vacuum reading is an Indication of a faulty diaphragm

Fuel Pump Vacuum Test

Disconnect gasoline feed line from fuel pump. Attach vacuum gauge hose to fuel pump inlet and start engine. The gasoline in the carburettor will run the engine for a sufficient time for this test. If fuel pump performance is satisfactory, the vacuum gauge reading should build up to 10 inches of vacuum.

Gasoline Line Test

Disconnect gasoline line at gasoline tank and attach vacuum gauge hose to gasoline line. Start engine. If there are no leaks, the gauge reading will be the same as on the fuel pump vacuum test above.

Fuel Pump Pressure Test

Caution: When carrying out the fuel pump pressure test, ensure that fuel connections are secure enough to hold the fuel pressure without leaking

Connect vacuum hose as close as possible to intake manifold and start engine. Run engine till normal operating temperature has been reached and then allow to idle. If carburettor is properly adjusted, the vacuum gauge reading will remain stationary between 18 and 21 Inches. If vacuum gauge pointer shows a slow floating from 21 to a lower value, the carburettor requires adjustment.

Note: Your vacuum gauge is designed with an impulse damper to prevent excessive pulsations of the pointer when making vacuum tests. This restriction is located in the stem of the gauge and could become clogged after long use. If this condition is suspected, remove hose at vacuum gauge and clean by inserting a small drill or stiff wire 0.015 diameter.