maintenance (pump)
Pump Vacuum Test
CAUTION
DO NOT attempt to start the engine unless the pump has previously been primed with water. Severe pump damage will occur if pump has not been primed.
To perform the pump vacuum test do the following:
1.Remove the pump fill cap (See Figure 2), and fill the pump with water.
2.Start the engine as outlined in the initial
3.As shown in Figure 17, place a water hose inside the discharge opening of the pump, and turn on the water. This flow of water into the discharge opening will prevent the pump from running dry.
4.Place the Pump Vacuum Tester (P/N 7000030) over the pump suction (inlet) opening (See Figure 17) with the vacuum gauge facing upwards. It may be necessary to apply a small amount of water around the rubber seal of the vacuum tester to make a good suction fit.
5.Check and make sure that there are no air leaks between the vacuum tester and the inlet port on the pump. If air leaks are present reseat vacuum tester.
6.Run the pump for a few minutes while monitoring the vacuum gauge. If the gauge indicates a reading between
NOTICE
25 in. Hg (inches of mercury) translates into 25 feet of lift at sea level.
7.If the vacuum tester gauge indicates a reading below
8.To test the flapper valve, shutdown the engine. The vacuum tester should remain attached to the pump suction inlet port by vacuum.This indicates the pump's flapper valve is seating properly to hold water in the suction hose when the engine is stopped.This prevents backflow and allows for faster priming when the engine is restarted.
Adjusting Impeller Clearance
1.If it is necessary to replace impeller or volute, be sure clearance between impeller and volute is adjusted correctly.
2.The impeller should be as close to the volute as possible without rubbing against it. Clearance is adjusted by adding or removing shims from behind the impeller.
3.Check clearance between impeller and insert by slowly pulling starter rope to turn impeller. Remove spark plug to make it easier to turn impeller.
NOTICE
QP305SLT only — It is important not to remove too many shims or the clearance between the impeller and volute will become too wide and pump performance will be reduced. Remember as the impeller wear down, additional shims may be required to maintain the clearance between the impeller and insert.
4.Check the impeller every six months for wear, and for clearance between the impeller face and the volute. Also check the shaft seal for wear, as well as the shaft sleeve.
CAUTION
The impeller may develop sharp edges. Use extreme care when checking the impeller to prevent being cut.
QP305SLT/QPT305SLT CENTRIFUGAL PUMP • operation and parts manual — rev. #1 (10/11/10) — page 19
