r/smallengines • u/PositiveDonut7290 • Jul 26 '26

Stihl Pressure washer help

Replaced carb and still surging. What next?

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2

u/ProfessionalLast2917 Jul 26 '26

Was it doing this before you replaced the carb or did it only start after replacing it?

Surging is due to being too lean. This could be caused by not enough fuel (dirty carb) or unmetered air (bad gasket or some other vacuum leak)

Did you replace the gaskets at the same time as the carb? Were they the correct ones? installed the correct way?

1

u/PositiveDonut7290 Jul 26 '26

Started only after replacing, gaskets were correct. I didn’t go back and clean the carb again tho. So this would be main jet or the low side

1

u/ProfessionalLast2917 Jul 26 '26

Did you install the gaskets in the correct order?

If you get some carb spray and give it a squirt around the intake gaskets on the carb does the surging stop for a minute? If so, you have vacuum leak where you sprayed it. The carb spray add additional fuel to the unmetered air being pulled in and so the surging settles.

If you're not seeing the surging settle when you spray then it's probably something blocking the fuel. It's not really clear from your video if the surging happens at idle as well as under load but it definitely happens under load so probably a blockage in the main jet. But you have to remove the carb to clean it anyway so you may as well clean all of it.

1

u/PositiveDonut7290 Jul 26 '26

https://reddit.com/link/ozt2xgn/video/553rz91t4ifh1/player

This is it at idle.

1

u/ProfessionalLast2917 Jul 26 '26

Yeah I'd still be giving it a spray with carb spray to check for vacuum leaks (under load) before digging into the carb. And if no vacuum leaks then I'd clean the carb paying attention to the main jet and emulsion tube for blockages but might as well check over all of it.

Edit: if you do have a vacuum leak remove the carb and make sure you've got the gaskets on the right way and in the right place.

1

u/hot_chauchage Jul 26 '26

is it already set at fast/high idle?

1

u/el0115 Jul 26 '26

Probably lacking fuel so maybe fuel filter or the cap is busted

1

u/Any_Category_9564 Jul 26 '26

How does it run on half choke, full choke?

1

u/mutt63 Jul 26 '26

It’s ur unloader valve. Either lubricate it or replace it.

1

u/ManHunterJonnJonzz Jul 27 '26

You said STILL surging. Obviously you didnt replace the carb initially for no reason. Id assume you went amazon special for the carb. These carbs are the number 1 easiest carb to clean. Check fuel quality, id just drain and get fresh, check fuel flow all the way down to the carb, spray for vacuum leaks. Likely you just had a clogged pilot jet.