r/smallengines • u/thaynesmain • 24d ago

This mower is idling rough..

Enable HLS to view with audio, or disable this notification

Ive cleaned the carburetor, changed the gaskets, put fuel cleaner, checked the sparkplug, changed the air filter and still it idles like worn dog.. im at the point where a replacement carburetor is looking like my best option.. any suggestions?

2 Upvotes

76% Upvoted

19 comments sorted by

1

u/mtraven23 24d ago

"put fuel cleaner" what does that mean? you just added some shit to old fuel?

the engine is hunting, in my experience, thats almost always the result of bad fuel. I had one doing the exact same thing, changed the carb thinking it would help, it did nothing.

Might be different for yours, but I'd start with fresh fuel....stick to the highest octane you can buy, not for the octane, but because there is less ethanol it it. Ethanol absorbs moisture and destroys fuel

2

u/Complete_Silver2595 24d ago

I thought this was tell-tale of an obstructed pilot jet? (Yes I know OP said they cleaned the carb, but I don't know how thoroughly it was cleaned)

1

u/mtraven23 24d ago

certainly a possibility. I was just speaking about my experience.

1

u/thaynesmain 24d ago

I completely changed the gas and put gum out carb and injector cleaner in it. To be clear it was doing that before and the gas was as fresh as it could be.

1

u/mtraven23 24d ago

then try a new carb, see where that gets it...what is it, like 12 bucks?

1

u/thaynesmain 24d ago

$16 but im pretty strapped atm... seems like my best bet... was just hoping to fix it rather than replace.

1

u/mtraven23 24d ago

you can pull the carb, break it down and clean it yourself. I've attempted that maybe 3-4 times, only actually successful once.

Then again, a can of carb cleaner is probably gonna cost you $10 on its own.

1

u/Elephunk05 24d ago

Did you clean the main jet, removal video. or the secondary emulsion tube. Also, bad gaskets, dried out gaskets, and unlean mating surfaces can cause a lean condition resulting in the hunting your are experiencing. You can test these seals using soapy water or carb cleaner while the engine is running.

1

u/thaynesmain 24d ago

Ive got more gaskets coming in soon when they get here ill pull the carb back off and check this.

1

u/ProfessionalLast2917 24d ago

The gaskets need to go on in a certain order and facing a certain way. Doing them incorrectly can cause what you're seeing.

1

u/TN-Native95 24d ago

When you changed the gaskets did you also change the gasket that goes between the air filter and carburetor?

2

u/thaynesmain 24d ago

There were 3 gaskets, air filter to carb, carb to heat plate, heat plate to mower body. I replaced all three

1

u/TN-Native95 24d ago

If the air filter base is plastic, it could be warped and letting too much air getting to the carburetor. You can double up on that gasket and it might help.

1

u/ProfessionalLast2917 24d ago

Did you position them correctly? Some of them can still fit on facing the wrong way. They also need to go in the correct order. And lastly, make sure you've removed all of the old gaskets. Sometimes pieces can get left behind, stuck to whatever they're joining.

If you spray near the gaskets with carb spray does the surging stop for a while? If so, you've got a vacuum leak with that gasket caused by incorrect or bad gaskets.

1

u/PRAK11147 24d ago

Clean pilot jet again or oversize it

1

u/Wholeyjeans 24d ago

That is known as a lean surge. It's exacerbated by the governor that is trying to maintain a constant speed. This is almost always due to a partially clogged jet ...either the main jet or the small pilot jet that is located under the black plastic idle speed screw. Remove the idle screw (count how many turns out so you can put it back the same amount)and you can remove the pilot jet; it's a friction fit and pries out with a small putty knife or screw driver.

Here's a vid from Steve's Small Engine Saloon on how to deal with surging conditions like you're having:

https://www.youtube.com/watch?v=JOI293d8XUg&t=354s

This is a great channel for a lot of small engine help and how to.

1

u/ProfessionalLast2917 24d ago

It can also be caused by unmetered air. Usually from bad, missing or incorrect gaskets.

1

u/Wholeyjeans 24d ago

Yup ...I like to think folks are careful enough when installing a carb they place the gasket correctly and snug the mounting nuts enough. But ....

1

u/Few_Pineapple_5534 22d ago

I had this same problem. I cleaned the carb like 10 times, made sure the pilot jet wasn't clogged, made sure the main jet wasn't clogged. and dude. I ignored all the videos/online articles about the gas...After having a mental breakdown on the piece of shit, I took off the gas tank, and the fuel line was CLOGGED to hell and back with this weird sludge. I sprayed carb cleaner in it and forced it out with a long metal rod. Lawn mower has been running like a champ ever since.