Why Is My Pump Experiencing Low/No Suction or Weak Discharge?

To troubleshoot low/no pump suction or weak discharge, check if the vertical suction lift and total head lift are within the allowed range, if the pump has been primed, if the end of the suction hose is submerged in water and suction hose strainer is obstructed, if suction hose or port is leaking air or water, if discharge hose or port is leaking air or water or if the discharge hose is blocked or restricted. Lastly, check the engine throttle lever and make sure it is set to the fast position.

  • Mar 7, 2025
  • Knowledge

Title
Why Is My Pump Experiencing Low/No Suction or Weak Discharge?
URL Name
Why-Is-My-Pump-Experienceing-Low-No-Suction-or-Weak-Discharge

Public Answer

Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns. 

Troubleshooting pump suction and weak pump discharge

To resolve issues of no suction or weak discharge in a pump, several steps can be taken. These include checking the vertical suction lift, total head lift, priming of the pump, ensuring that the suction hose and strainer are submerged and not obstructed, verifying that the suction and discharge hose or port is not leaking air or water, ensuring that the discharge hose is not blocked or restricted, and setting the engine throttle lever to the fast position.

If a pump is experiencing low/no pump suction or weak discharge, it is important to check:
 

  1. Vertical suction lift is too high: Most Generac pumps have a maximum Vertical Suction Lift of 26 ft.​

  2. Total head lift is too high​: Depending on the Generac Model, Max Head Lift can vary from 80 ft to 149 ft. ​

  3. The pump has not been primed: Generac pumps must be Primed before startup. If the engine has shutdown for any reason, the pump will need to be primed again.​

  4. The end of the suction hose is not submerged in water or the suction hose strainer is obstructed: The end of the suction hose must be fully submerged in order to form a suction.​

  5. Suction hose or port leaking air or water: Verify the Suction port gasket is in place and the hose clamp is tight. Replace the gasket if damaged/worn.​

  6. Discharge hose or port leaking air or water: Verify Discharge Port Gasket is in place and hose clamp is tight. Replace gasket if damaged/worn.​

  7. Discharge hose blocked or restricted: Do not restrict the discharge hose in any way. ​Verify discharge hose is completely unraveled with no major kinks.​

  8. Engine throttle lever set to the slow position: Move the throttle lever to the fast position.​

Was this article helpful?
Upload Files


Need more help? Get in touch with our support team.


Contact Support