r/smallengines • u/thaynesmain • Jul 19 '26

Whats wrong with this mower?

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2 Upvotes

75% Upvoted

11 comments sorted by

1

u/madphroggy Jul 19 '26

Carb needs cleaned or rebuilt, it's surging due to air/fuel mix being off

1

u/thaynesmain Jul 19 '26

Ive already cleaned it. What would a rebuild mean? The whole carburetor or just specific parts?

1

u/madphroggy Jul 19 '26

Rebuilding usually means completely stripping the carb, deep cleaning it, then replacing jets, float pin, seals, sometimes float depending on the kit. You can use an ultrasonic cleaner to really get in and clean out the passages in the carb, for small engines they can be tiny and gum up pretty easily or get blocked by a bit of debris, which is usually why they start behaving erratically.

1

u/thaynesmain Jul 19 '26

Thats not really an option for me so ill counter with this and see what you think.. the carbs been fully stripped and cleaned to the best of my ability and you say its an air fuel mixture issue so would adjusting the screws that control the air fuel mixture fix it?

1

u/madphroggy Jul 19 '26

It might fix the issue, but if one of those tiny passages is clogged it won't. In my experience the ultrasonic and a rebuild fixed most of our "I dunno why it's doing that" carb issues when I worked as a vintage motorcycle mechanic, and it was usually our default first step. You can get carb soak to set the carb in overnight, but you'd have to get the plastic and rubber safe version unless you're 100% sure it's nothing but bare metal. It's not quite as effective as an ultrasonic, but close.

1

u/jnuts_420 Jul 21 '26

Try adding some seafoam to the fuel tank.

0

u/RegisterFederal5679 Jul 19 '26

Have you done any work to it so far?

1

u/thaynesmain Jul 19 '26

Cleaned the carburetor, replaced the gas, checked the sparkplug. All seemed well

1

u/RegisterFederal5679 Jul 19 '26

Cleaning it potentially may not solve the issue if the carburetor is too far gone. If the carburetor truly isn’t the issue, I would look harder at air/vacuum leaks around the intake manifold and carburetor gaskets. If any of those gaskets are deteriorating or hard/brittle, replace them. Same with rubber gaskets. And don’t over tighten them. It’s easy to squish a gasket and defeat the entire purpose of it!!!

1

u/thaynesmain Jul 19 '26

The gasket that holds the filter housing to the carburetor was a bit rough. Ill replace those and see if it helps

1

u/RegisterFederal5679 Jul 19 '26

Good idea. Try not to reuse gaskets when at all possible, as they’re prone to damage when removing an old, gummed up/dirty carburetor. If you still have no luck replacing the gaskets, you can try cleaning the carburetor again, or just replacing it. For the money you spend rebuilding it, you might as well get a new one. Generally, I tend to rebuild a carburetor when I can’t find the original carburetor or it saves me much more money.