I've got a mower I bought from Sears in 2004, 5.5 horsepower engine Series 123K02, I think.

I have the bad habit of leaving gas in it over the winter. I've been OK doing that, and been OK using old gas from last year, too. Yeah, I know. Don't do that.

I pulled out the mower today, topped off the tank and it fired up easy on the first pull, as usual, then ran for about 15 seconds, dipped in idle briefly, came back up, then died. Won't start since then, not a peep. I drained the old gas out, put new gas in, still won't start. I pulled the plug, doesn't look fouled but I scraped it anyway. I don't have my gapper handy but the plug has had maybe 12 or 15 hours on it since being installed. A new air filter was installed last year.

I noticed in a parts manual for the engine that it says if you tip the mower (which I did to drain the tank) the tank must be empty. (uhh) Well, it wasn't, and the manual says if you tip it over all the way, gas can foul the air filter and the plug can get oil-fouled.

This was all this evening so I didn't have time to start checking much. I may have just flooded the thing since I pumped on the little priming bulb a lot while trying to get it to fire up.

It does seem to me that since it fired up immediately on the first pull since last year, then died quickly, it is probably a fuel issue.

I looked online and I do see stuff about old gas lacquering carb parts or the fuel line or filter. I am no mechanic but if it's a fuel system issue, I guess youtube and SIGforum can coach me through it.

I wonder if since I might have flooded it, it might just fire up tomorrow, but I have a feeling I won't get that lucky.

Any advice is welcome.

My guess is that the float is stuck in the carburetor.

This has all the earmarks of a fuel starvation issue. In addition to carb-related problems, blocked orifices, gasket failures, etc., check that fuel delivery to the carb is adequate. A pinhole in the fuel pickup tubing will prevent this. Also an air leak where the tubing connects to a fitting. Inside the tank, there will be a filter that can get clogged with water or debris, it doesn't take much.

Spraying ether/starter fluid into the combustion chamber can help eliminate spark or compression deficiencies.

A healthy dose of Seafoam or Techron in the gas . Get a can of starting fluid and give it a shot in the intake . It'll probably crank and run for about 3-4 seconds . Repeat a half dozen times . Then let it sit overnight . The next day there's a good chance it will crank and run . I've used this method three times to revive a mower that sat up too long . Did it this week in fact . It's worth trying before you start taking things apart or haul it to the shop .

My 2 cents.
Check to make sure the plug sparks.
If you have spark I next expect leaving the gas in it over winter gotcha. I would pull the carb off and put it in a pot of boiling water for about 20 mins. Roll it around during that time. Dump all the water out of carb and if you can blow it out with compressed air.
Reinstall, pull it a few times and maybe spray starting in carb.
My dad taught me that trick 60+ years ago.
It has worked about 95+% of the time. Usually don't even need to adjust the carb.

^^^^^^^^^^^^^^^^^^^
Yep good advice. The lawnmower shop keeps busy with stuff like thats. The worst is leaving it out in the rain all winter with stale gas. Briggs and Stratton makes good engines and 2004 model means you have been doing something right.

first test is take some starting fluid and spray it in the intake and see if it will start. If you don't have starting fluid you can use flammable contact cleaner. Second step is pull the plug on the carb and drain the bowl. That will get the old gas out of that part of the system. Third step disconnect the fuel line to the carb and move gas through it so the old fuel is gone from there. If it started and ran for 15 sec. this is a fuel issue.

If you have the plastic carb, there is a known issue with the flapper sticking.
Pull the air filter off, then take off the 4 bolts holding the air filter box on and remove the air filter box.
Manually operate the carb flapper by pulling the link behind the carb. The flapper should open and when released the spring should pull it back closed. The big plastic piece on the left side will sometimes hand up on the body of the card not allowing the flapper to close.
Use a small file and file the outside edge of the plastic piece until it opens and releases freely.
Reassemble and you should be good to go.

quote:

Originally posted by hrcjon:
Second step is pull the plug on the carb and drain the bowl.

I appreciate all the advice but you have to speak to me as if I'm not a mechanic or even from this planet. What "plug"?

As far as the composition of the carburetor, the engine was made in 2003 so I am fairly confident that the carburetor is not plastic. I'll find out tomorrow.

My advice is to pull off the carb and give her a proper cleaning. There will be two long screws or bolts holding the carb in place. Take a picture of the top of the carb showing how the linkage is hooked up...it's easy to forget. undo the linkage by twisting the carb as needed.

First remove the bottom screw or bolt to inspect the float. Go slow here as there are small o-rings that can be re-used. When gas fills the bowl the float rises and engages a small needle valve that shuts off the gas. Leave the needle valve alone, just blow some air around it. Spray brake cleaner fluid through all holes/orifices then blow out everything with compressed air.

Before reinstalling the carb take a close look at the bulb and the two gas lines running to the gas tank. Splits or cracks in any of those will stop you dead. They are easy to obtain at any auto parts store. Finally get a long stiff wire and bend the end into a hook and use that to fish out the filter which should be on the end of one of those gas lines. You should be able to pull it out thru the tank filler hole. Replace it or clean it with compressed air.

Good luck!

Take a look at this lady's channel on YT. She had been skeptical of this particular product until she actually tested it.

https://youtu.be/MmKSrkHjojc?si=Nygfdb9rY41uG6ZJ

quote:

Second step is pull the plug on the carb and drain the bowl

Almost every carb has a drain plug on the bottom of the bowl. Sometimes they don't but then they have bolt that goes through the bowl to fasten it to the carb. On those you just remove the bolt and the bowl comes off and you can ditch the gas and also look to see how much crap is in there.
I know some are advocating to clean the carb. That is definately NOT in the I am not a mechanic area. BUT what might be is that the carbs on these are incredibly cheap so a carb swap is probably something you probably will be able to do. Although I'm capable of it I almost never clean a carb anymore as its just way more efficient to just swap one. And the success rate is not stellar anyway.

quote:

Originally posted by selogic:
A healthy dose of Seafoam or Techron in the gas . Get a can of starting fluid and give it a shot in the intake . It'll probably crank and run for about 3-4 seconds . Repeat a half dozen times . Then let it sit overnight . The next day there's a good chance it will crank and run . I've used this method three times to revive a mower that sat up too long . Did it this week in fact . It's worth trying before you start taking things apart or haul it to the shop .

So, the starting fluid will allow the engine to fire up briefly, which helps to move the bad gas through the fuel line, and overnight, the fresh fuel will migrate into the line and mix with the old fuel so that there's enough good fuel to unstick anything that's stuck in the carburetor, and allow the engine to start, and once it starts, the bad fuel will quickly be gone.

Is that the idea?

.[/QUOTE]So, the starting fluid will allow the engine to fire up briefly, which helps to move the bad gas through the fuel line, and overnight, the fresh fuel will migrate into the line and mix with the old fuel so that there's enough good fuel to unstick anything that's stuck in the carburetor, and allow the engine to start, and once it starts, the bad fuel will quickly be gone.

Is that the idea?[/QUOTE]

The starting fluid verifies that it's not getting fuel, it's gravity fuel feed from the tank to the carb, so running it might help get the fuel moving. When fuel evaporates it leave one hell of a varnish mess inside the carb. Running it with seafoam in the tank and with starting fluid in the intake, with luck, might clean the carb out.

This stuff?

https://www.walmart.com/ip/Sea...VARIANT&athbdg=L1103

Yes

You said "with luck". Where do I get that? WalMart doesn't stock it. I checked.

The gas probably has water in it unless it was ethanol free or treated. Gas with ethanol will suck water from the atmosphere over the winter. That water probably made it's way into the bowl of the carburetor.

OK, I'm gonna take a can of Lysol and a BIC lighter and make a flamethrower and shoot it at the carburetor to burn off the water.

I've used WD-40 with success as starter fluid. hrcjon is dead on and draining the bowl is easy on most, typically a small hex head that you loosen and an oz or so old gas will drain. I like Startron as a fuel additive.