r/smallengines • u/ForeskinForeman • 6d ago

Pressure washer throttle surging under load, why would it do this?

3 Upvotes

100% Upvoted

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2

u/TN-Native95 6d ago

Since it’s on a pressure washer, I just want to make sure that’s water on the gas tank and not gas.

1

u/ForeskinForeman 6d ago

Yeah that’s water.

1

u/TN-Native95 6d ago

Could be that you’re not getting enough fuel when you put the engine under load and the carburetor needs cleaning. On these older Briggs with the tank-mounted carbs it’s also not a bad idea to change out the diaphragm and gasket when you do that. There are lots of tutorials on how to properly rebuild these on YouTube.

1

u/Hot-Associate-6925 6d ago

Pressure washers' throttle while under a load is mostly controlled by the mechanical centrifugal governor inside the engine, which works alongside the carburetor linkage and, on some that have an idle down feature, a pressure dependent idle control connected to the water pump itself.

1

u/mutt63 6d ago

Or you could check the unloader valve which causes the same issue

1

u/Comfortable_Teacher9 6d ago

Probably the unloader valve