Multiquip QP4TH Benutzerhandbuch

To perform the pump vacuum test do the following:
1.  Remove the pump fill cap (See Figure 3), and fill the 

pump with water. 

2.  Start the engine as outlined in the initial start-up 

section, and wait for the pump to begin pumping.

3.  As shown in Figure 18, 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 18) 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 -25 and -20 in. Hg. (inches of mercury) then 

it can be assumed that the pump is working correctly.

7.  If the vacuum tester gauge indicates a reading below 

-20 in. Hg, it can then be assumed that the pump is 

not functioning correctly, and corrective action needs 

to be taken.

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.

25 in. Hg (inches of mercury) translates into 25 feet of 

lift at 

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.

1.  If it is necessary to replace impeller or volute, be sure 

clearance between impeller and volute is adjusted 

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.

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.

After pumping water containing large amounts of dirt and 

debris, perform the following:
1.  Remove the drain plug from the pump housing 

(Figure 3) and drain any water left in the pump.

2.  Loosen the two locking hand knobs (turn 

counterclockwise) and remove clean-out cover.

3.  Clean and remove dirt, debris from pump casing. 

Inspect impeller and volute for wear. Replace any 

damaged or worn parts.

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.

The impeller may develop sharp edges. Use extreme 

care when cleaning around the impeller to prevent 

being cut..