Boat won’t suck water

[Kristyn]

Replaced impeller in my 1999 Volvo Penta 5.0 and I can not get the boat to suck water when muffs are hooked up! Any suggestions?

 

[muc]

Hi, Welcome to iBOATS.
To help you with the most common causes of not pumping water. We might need more info.
Is the pump belt drive or mounted to the front of the crankshaft?
Do you have a model number or serial number?
Are you replacing the impeller as normal maintenance or because it quit working?

 

[Kristyn]

The impeller and housing is mounted to the crankshaft. We are replacing the impeller because my husband had a hard time winterizing the boat and the impeller was missing fins.

The serial number is 4112063614
and I’m not sure about the model number

 

[muc]

Thanks, that helps me.
Make sure the hoses are on right. The intake hose (the one that comes from the transom) goes to the top. The hose that goes up to the thermostat is on the bottom.
Take it back apart. If you didn’t find all the broken pieces, they can get sucked back into the pump and ruin the new impeller. Also those pieces can plug up the thermostat housing. While it’s apart, make sure that the old oring got removed. Two o rings will cause this.
The pump might be an older style that has plastic tubes that the hoses slip over. Those tubes are pressed into the metal housing and can get loose. Loose is bad and you will need a new pump.
Use liquid dish soap to lubricant the impeller, it will help it develop suction.
Use a garden hose to back flush the intake hose and make sure that the only place water comes out is the intakes on the drive.

 

[Kristyn]

Thank you! I think the housing is the issue now. The tubes coming off the impeller housing are loose. I tried duct tape to see if I could get a tight enough seal but it still won’t suck water.

 

[muc]

Might want to try priming it.
With the muffs on the drive and water full on.
The hose that goes from sea water pump to thermostat housing.
Remove it at thermostat housing.
Squirt dish soap in hose and then fill the rest of the way with water.
Watch water level for 30 seconds, it should stay stable.
Reconnect hose and try starting.

 

[Kristyn]

We did that and it still did not suck.

 

[muc]

We did that and it still did not suck.

That trick (if all the steps are followed correctly) will get engines that the only problem is loose hose nipples pumping. I think you also have other problems.