Craftsman mower won't start

I'm frustrated and have a headache from all the gas fumes and heat. And my hands reek of gas which is making me nauseated so please forgive any crankiness.

Craftsman mower, Briggs & Stratton engine, 190cc, 625 series, 22" cut, self-propelled

This is my 6th or 7th time mowing this season. All was well until yesterday. Engine sputtered then died. Now won't start. Here's what I did in sequence.

Drained the gas. Added several ounces of Seafoam. Added more gas. No go.
Drained the gas again. Removed the carburetor and cleaned it with carb cleaner. Including the fuel line from the tank to the carb. Carb looked fine, no build up, no varnish. It looked new still.
Got it to start and run for about 3 minutes. It blew a lot of white smoke as it was running. Then it died again.
Left it overnight out of frustration.
Today, I replaced the spark plug and air filter. Changed the oil which was pretty gross. I possibly added the wrong oil last month (but it has been working ok until yesterday). Tried to start with the gas cap off in case the air vent was clogged. No go.

The string pulls normally. It just won't start.

Is there anything else I can try? The gasket on the carb looked fine. There was a gaskety looking thing where the carb and the part where the air filter goes was a little wonky, but not terrible. Is that the diaphragm? I saw a video about replacing the needle, but since the carb looked clean in the first place, is that something to try? Should I try to replace the whole carburetor?
I don't understand why it started and ran for a while, then died again. What was the white smoke?
I am not mechanically inclined so I don't know the terminology. However, I can watch a video (usually) and follow the instructions which is how I cleaned the carburetor.
I appreciate all your advice in advance.

 

Is there any chance you overfilled the oil? The white smoke was oil. it could be from changing the oil (did you have it tipped over?), or it could be from being overfull, from overspeeding of the engine, or from gas being in the oil, making it thin and overfull. Take the spark plug out and see if it is oily.

 

Thank you for responding on Father's Day.

I pulled the spark plug, and it did have a tiny amount of oil on it. Not even enough to see but a small amount came off when I wiped it with a paper towel.

I did tip the mower over to change the oil this morning. The white smoke was yesterday. I didn't tip the mower then. Would it still be oil making the white smoke? If so, why would it smoke after cleaning the carb and not before? Just curious.

I checked the oil dipstick and it is overfull. I can drain some out, but if gas got into the oil from tipping, should I change it completely again?

What steps should I take next?
Thanks again.

 

Check the oil for a gassy smell. If it is thin and smells like gas, drain it all and fix the leak in the carburetor. If it's not thin and gassy, then drain the appropriate amount and see if it will run. If it is overfull of oil, it may have soaked the air filter with oil. If so, replace it.

Tipping it wouldn't have gotten gas in the oil unless it was tipped for a pretty long time.

 

So first of all, what carburetor is this,,,,,,,is it plastic?? Does it have a float bowl on it?? If you say it MAY have a diaphragm on it and you took carburetor off and put it back on, you more than likely need to replace that diaphragm, also get oil to proper level. A model number on engine would help us a ton.

 

The saga continues. I installed a new gasket between the carburetor and the air filter today. Again, drained all the gas. Cleaned everything again. Started to drain some of the oil and it was nasty. When I put the new stuff in last weekend, it was golden colored. Today, it was charcoal colored. What would make that happen? I drained all of that out by tipping it over. I wasn't able to find the oil plug under the deck (stepdad told me to do that). There's a plastic piece that covers the belt that I couldn't easily remove and didn't want to break.

So I'm guessing that there's something wrong with the engine since the oil turned black even though it wasn't run at all. Sigh.

I put half a bottle of B12 in the empty gas tank. Got fresh from the pump gas and put some in. Changed the oil. Still no start. Tried carb cleaner and a spritz of gas in the muffler too (also a stepdad trick).

And my stinking truck won't start so I can't even take it to Land and Coates today! Grrr.

Thanks again for all the advice. Due to the oil element, I'm assuming this is something I won't be able to fix with my very limited knowledge.

 

Don't worry about the color of the oil, just the level of it. If you drained it by tipping the engine over (not the best way to do it), you may have some in the upper cylinder. Don't worry about that. You may get some smoke at startup, but it will burn out in a short time. Just don't start it in a closed building.

Fill the crankcase with new oil to the proper level, then put a teaspoon of gas in the plug hole and tie back the plug wire to prevent arcing. Now spin the engine over a couple of times with no choke and full throttle.

Then put the plug back in, hook up the plug wire, and, with no choke and half throttle pull on it until it starts.

 

You are over doing the carb cleaner stuff, when you pour 1/2 bottle of B12 in an empty tank and then gas you have a carb full of B12 and no gas. The white smoke previous was probably from too much Seafoam, also all modern push mowers change oil by dumping the oil out of the filler tube, anything to save a nickle. OK, since you didn't post the engine model, type and code I will guess it has a bowl type carb, so now drain the tank, remove the carb bowl(must get rid of that B12), the nut that holds the bowl on is the main jet, it has a hole down the center and a hole through the bottom, make sure they are clean, put the bowl back on. If you removed the air filter housing be very careful when you reassemble so as to not destroy the gasket, if it is damaged the primer won't prime since the gasket is part of the priming circuit. Remove the spark plug and crank over the engine 10-20 times to clear whatever B12/Seafoam is setting in the cylinder, check to make sure you have spark(should have done that in the beginning but I don't want to retype this). Make sure the oil is at the proper level, now add fresh fuel(fresh from the pump not fresh from a can that has sat for 2years), leave the carb cleaners on the shelf, let it set for a minute so the carb can fill, then prime it and you should be good to go. Have a good one. Geo