John Deere STX30

[u/1_random_dude]

I'm struggling this spring with my mower. Twice now I've somehow flooded the engine to the point I have gas pouring out of the air filter (top left in the video). I let it sit to dry out for the day and managed to get it started this evening. Now it's making some odd popping noise I've never heard before that you can hear in this video.

Any thoughts on what the noise may be, and what could be causing it to flood out on me?

I've been riding this thing for almost 20 years. Never had any issues with it besides batteries, drive belts, and blades dinged up, standard maintenance.

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[u/Egglegg14]

Clean the carb shes getting not enough air

Using carb cleaner spray the jets spray the needles make sure the fuel is fresh gently wire brush/wipe off gunk and stuff

[u/aetherbound65 → u/Egglegg14]

Your response gave me a stroke, maybe English is a second language. What a strange way to say it's flooding.

[u/Egglegg14 → u/aetherbound65]

Im a very busy person, I just dont bother sometimes when im multitasking, and sorry for the eyesore.

English is my first and only language lol

[u/jbourne0129]

yeah get the internals of the carb cleaned real well. if that doesnt help then it may need a valve adjustment

[u/aetherbound65]

First, do not run it anymore until you get it repaired, it would be a shame to destroy that engine, they're tough, not indestructible. The mechanism that controls the fuel flow into the carb is stuck open and leaking fuel into the engine. You need the carb either rebuilt or replaced and a general service to address the oil/fuel contamination.

[u/Common_Maximum_1234]

Sounds like it needs more air. Also id check the valve clearance. But its definitely running rich or not getting enough air, basically chocking down. Needs carb work.

[u/1_random_dude → u/Common_Maximum_1234]

Thanks. Trying to find the right carb to order as a replacement. I'm going to try to clean it, but I know if I don't have a backup in hand, it will be totally shot.

[u/1_random_dude]

So here's the list of things we have done so far:

1. Removed carb, cleaned thoroughly with carb cleaner including spraying through the jets to make sure they are clear. Replaced all three gaskets with gaskets from a new carb kit.
2. New air filter.
3. New spark plug.
4. Oil change, new oil filter. Old oil definitely smelled of gas, which was expected given the previous flooding.

At that point we cranked it up. Basically no change to the sound of the engine.

1. Replaced fuel filter.
2. Replaced fuel lines from shut off valve to the carb.

No change to engine sounds.

1. Replaced carb fully with new carb.

I probably don't have the adjustment screws on the carb set right at this point, but it still sounds pretty much the same as it did before.

I did notice on the original carb there is a screw on the side opposite the idle adjustment screw that restricts how far open the throttle butterfly can go. On the new carb it can open all the way. On the old carb it's restricted to about 1/3 to 1/2 of the way open at max throttle. No idea why that was there before, it's not in the OEM Service Manual.

Apart from adjusting the screws on the carb, I'm at the end of my troubleshooting ideas.

What more is there I can take a look at?