What to do if Yellow Jacket Water Pump has poor vacuum?
- AAustin HernandezAug 16, 2025
A poor vacuum could be due to dirty oil, a loose drive coupling or set screw, a bent or broken exhaust valve, the pump not oiling, or malfunctioning vanes. Flush the pump one to three times. Repair or replace the drive coupling or exhaust valve. Contact the factory for issues with oiling or vanes.