Clearing a clogged foam lance orifice

Unclogging a power washer foam lance


I purchased a MATCC Foam Canon / Lance a while back. It worked like a charm. I tried to use it this summer and it wouldn’t draw from the bottle nor would it foam. The solution was simple


A power washer foam lance or foam canon consists of an nozzle that fits on the end of your power washer gun. It has about a quart bottle that holds soap. When you pull the trigger, the soap is mixed with air and soap to create a foam. With my 1800 PSI electric power washer, I can squirt foam to the top of the peak over my garage. That is about 2 stories. 

When I tried to use it this year, it wouldn’t draw the soap nor would it foam. 

The basic design

The design is simple. A bottle holds your soap. A plastic tube reaches to the bottom to pull the soap from the bottle. The soap feeds through a small orifice and the venturi effect mixes it with the water and air. The weakness is that the orifice is extremely small and the least bit of debris will clog it.

The problem – a paper seal

I disassembeled the nozzle and found that the orifice was clogged. When I opened the car wash bottle the previous year, I allowed pieces of the paper seal to get into the soap. That got sucked through the hose and instantly clogged the orifice.


Disassembly was fairly easy. Remove the bottle. Then remove the hose from the barbed fitting.

Clearing a clogged foam lance orifice

In this case, the barb was metric. Gently clamping the lance in a vise and using the proper sized socket made removal easy. 


With the barbed fitting removed, you can see the orifice.  You can clean that out with running water, carb cleaner, compressed air or whatever. However do not try to clean it out with a pick. 

As I was reassembling it, I realized that any debris would cause another clogged orifice. I happened to have a new filter from a weed wacker. I wasn’t sure if it would allow the soap to pass through but so far it works. I’m currently using a mix of 3/4 clorox and 1/4 car wash soap. I haven’t tested it with straight soap. If it doesn’t work, I can simply pull it off the hose. 

I also used a gasoline funnel with a fine wire mesh to remove the remains of the paper seal from the soap. 


The results were a fully functional foam lance. Yes, they are ‘only’ $20 but twenty bucks is twenty bucks. Plus with the covid disruption, amazon might take a couple of days to deliver.

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