Symptoms
- Only plain water comes out with the soap nozzle on
- Detergent bottle level doesn't drop while spraying
- Soap dispenses weakly or inconsistently
- Worked before but stopped suddenly
Likely causes
- CommonWrong nozzle tip installedDetergent only draws in through the low-pressure black or specific soap nozzle; any other tip creates too much pressure to siphon.
- CommonClogged detergent siphon tube or filterThe small filter at the end of the siphon tube in the bottle can clog with dried soap residue.
- PossibleDetergent too thick or wrong typeSome detergents are too viscous to siphon; using pressure-washer-rated detergent, diluted per instructions, usually solves this.
- PossibleCracked or disconnected siphon tubeA tube that's cracked or has come loose from its fitting will draw air instead of detergent.
- PossibleDetergent injector clogged inside the machineDried soap can clog the small injector valve if the machine wasn't flushed with clean water after last use.
What to do
- Confirm the low-pressure soap nozzle (often black, wider spray) is installed, not a high-pressure tip.
- Check that the detergent bottle isn't empty and the siphon tube reaches the bottom of the liquid.
- Remove the siphon tube's filter screen and clean out any dried residue.
- Inspect the tube for cracks or a loose connection at the machine, which would let it draw air instead of soap.
- Try a fresh, pressure-washer-rated detergent diluted as directed, since thick or wrong soap can fail to siphon.
- Run clean water through the detergent system briefly after each use going forward to prevent buildup.
- If detergent still won't draw with a clean tube and correct nozzle, the internal injector valve may need cleaning or replacement by a repair shop.
Tools and parts
- None required for basic checks
Pressure washer detergent siphon tubeSearch: “pressure washer soap siphon hose replacement”
Pressure washer detergentSearch: “pressure washer rated detergent soap”
When to call a pro
If the siphon tube and injector are clean but soap still won't draw, a small-engine or pressure washer repair shop can inspect the internal injector valve.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.