North Star M157116C.2 Owner's Manual page 52

Causes
Inadequate detergent supply
High pressure hose too long
Chemical strainer or injector clogged
Troubleshooting
POOR OR NO DETERGENT SUPPLY
Solutions
Refill detergent container. Make sure chemical strainer is fully
submerged.
Use less hose. Move machine closer to the work.
Clean the strainer and injector. Always start with a clean detergent
container. Run clean water through the injector after each use.
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