Craftsman Push Mower Starts and Stalls

[99Saturn]

Small engine novice here.

I have an oldish craftsman self propelled push mower that I picked up used earlier this year. Basically, acquired from someone that had let it sit for a few seasons unused. Didn't have gas in it when I was picking it up and was offered free as is so it was not like they were trying to hide anything. One part missing which is the handle, I swap another handle from a spare mower which is not an exact fit but works.

Brought home, figured just for kicks fresh gas and would give it a pull and see what happened, started right up. Do a little poking around, oil was a little overfilled (drained and refilled), lots of debris here and there (cleaned out the air filter), residue on the carb and back of the air filter housing (assuming from gas sitting at some point, or from lack of use when it was in service - small lawns where I picked it up and likely stored outside), put on the to do list.

Life goes on, I cut the lawn a few times and have cycled through 3 or 4 tanks of gas. Go to start it a week or two ago and it starts, no problem, I go to mow, 5 or 10 minutes in it stalls. Go to pull to restart and best I can do is get it to turn over and immediately stall. Remove air filter try to start, no improvement (starts and stalls), new spark plug try to start (starts and stalls). At this point figure time to clean the carb, or something is causing it to not get gas. I remove and disassemble, brake cleaner/carb cleaner everything and reassemble. Pull to start, it starts and stalls. Ok, frustrated, do something else and come back an hour or so later. About to show my lack of knowledge of more troubleshooting from here...

I think to myself, wonder if the handle being slightly wrong is causing the wire that controls the choke to not fully pull and do its thing. Pull the handle and place a small wooden block where the choke wire moves/attached to the engine to keep it pulled "a little bit more". Starts right up. Okay, I mow and consume the entire tank, but still have a little bit left to mow. Take a break, grab some water, refill the tank, turns over and stalls, try the block, turns over and stalls.

Most advice online for the usual suspects stops at the carb cleaning. So wondering what to check/do next?

Pictures to give an idea of what model I'm working with, it is a no prime/self prime start.

 

[dadto2]

I had a similar problem with a Snapper last weekend. (Similar Briggs engine) I was running like the gas was restricted. Would start right up and immediatly die. Had to wait 15-20 seconds before it could repeat.

I removed the carb, cleaned everything out of it, reinstalled. The problem persisted for about 10 more starts, then voila! Ran it for an hour while cutting the grass. Seems fine now.

 

[fantastic]

Spray some starter fluid to see if it will fire & we'll go from there.

 

[99Saturn]

spray some starter fluid to see if it will fire & we'll go from there

No change/impact from starting fluid, it starts and stalls (with or without fluid), lol with the exception of the time mentioned above that I got it to stay running for the bulk of the lawn.

My (simple and novice) thought was perhaps obstruction in either the fuel line or tank, but given that it ran for the entire tank without nursing it...

 

[Escape08]

One of my mowers have the same engine as yours. Whenever there's a problem not running right I always clean the jet at the bottom of the fuel bowl. I just bolt it out at the bottom and clean. It takes less than 5 minutes and the mower is back to normal.

 

[samven]

I am not familiar with that engine but it sounds like you have trash in the gas tank. Something is restricting the flow but not constantly. The fuel line may have swelled inside, there might be residue build up in the tank and line and the addition of Ethanol is starting to break it down and wash it into the carb. I would pull the fuel line at the carb and drain the whole tank through the line into a jar, reclean the carb and if it has a carb with a float, check the float level and the needle seat.

 

[tmorris1]

I have the same mower basically. Look between the muffler and the engine. There might be a auto choke that is thermally operated. It chokes the engine until the muffler heats up enough to move the lever to take it off choke. It might need to be replaced, but in my case I just cleaned the area up and it worked. It had a bunch of debris that was not letting the auto choke work. I bet this fixes your problem.

 

[tmorris1]

The part looks like this:

https://www.amazon.com/gp/product/B0153DMWEU/ref=ox_sc_saved_title_7?smid=ATVPDKIKX0DER&psc=1

 

[99Saturn]

I have the same mower basically. Look between the muffler and the engine. There might be a auto choke that is thermally operated. It chokes the engine until the muffler heats up enough to move the lever to take it off choke. It might need to be replaced, but in my case I just cleaned the area up and it worked. It had a bunch of debris that was not letting the auto choke work. I bet this fixes your problem.

Any "check process" to test these? I get the point about the clean up, just trying to avoid throwing parts at it. I've seen a few videos about these on other mowers but always just they turned out to be bad rather than being able to test them.

 

[jws555]

Does it use an air vane spring on the auto choke? Is it present and working? Two years ago neighbor's Toro
was missing one and wouldn't start.

Regards,
John

 

[MolaKule]

My thoughts were,

Trash in Carb bowl,

Trash in tank,

choke link bent or crud at carb

vane link bent or crud at carb,

kill switch wire or wafer spring touching something after warmup.

 

[fantastic]

No change/impact from starting fluid, it starts and stalls (with or without fluid), lol with the exception of the time mentioned above that I got it to stay running for the bulk of the lawn.

My (simple and novice) thought was perhaps obstruction in either the fuel line or tank, but given that it ran for the entire tank without nursing it...

If it's starting then stopping then it sounds like it's running out of fuel. Unfortunately, most of these mowers did not come with a fuel filter on them. I always recommend getting one to put on the fuel line coming out of the tank. It may take another round of cleaning the carb. If this fails then it may very well be the choke system not functioning very well for some reason. I think the ready start engines used some sort of wind vane to operate the choke? IDK

There very well could be some junk in the tank & lines. That's how the debris enters the carb.

 

[BigCahuna]

If you have an air compressor, use it to blow out the gas tank and the lines to be sure there's no junk in there. Make sure the carb is blown out with carb cleaner also. There are only a few things that will cause it to not have gas flow. Be sure your mounting gaskets are not ripped or torn. It won't run if your sucking air.,,

 

[mk378]

That looks like it's an air vane choke, which is actually a pretty good system. Standard maintenance on any mower engine is to take the top covers off and clean out the air passages. There is very often a mouse nest in there which will cause overheating and also may disrupt operation of the choke.

The main action of the air vane is that if the engine is turning at all, it pushes the vane forward and the choke opens. There is a thermal coil that stops the vane from moving back to closed if the engine is warm. This prevents flooding on attempting a warm restart but it doesn't sound like that's the problem here.

If it runs for a bit then won't fire at all until it has cooled off you should consider the spark plug and the coil. Spark plugs become intermittent when they crack inside. There is no way to see this visually, check it by substituting another plug.

 

[tmorris1]

Any "check process" to test these? I get the point about the clean up, just trying to avoid throwing parts at it. I've seen a few videos about these on other mowers but always just they turned out to be bad rather than being able to test them.

I don't really know of a formal check. I would clean it up and make sure it can move without any problem. You could also start it and watch to see if it moves or even use a torch or something to heat it up and check for movement. I cleaned and manually moved mine around and I haven't had another problem for several years. My mower has to be close to 20 years old. Looks the same as your except with the tall rear wheels, 22 inch cut and self propelled. Still starts on 1 pull usually.

 

[97prizm]

I had

Small engine novice here.

I have an oldish craftsman self propelled push mower that I picked up used earlier this year. Basically, acquired from someone that had let it sit for a few seasons unused. Didn't have gas in it when I was picking it up and was offered free as is so it was not like they were trying to hide anything. One part missing which is the handle, I swap another handle from a spare mower which is not an exact fit but works.

Brought home, figured just for kicks fresh gas and would give it a pull and see what happened, started right up. Do a little poking around, oil was a little overfilled (drained and refilled), lots of debris here and there (cleaned out the air filter), residue on the carb and back of the air filter housing (assuming from gas sitting at some point, or from lack of use when it was in service - small lawns where I picked it up and likely stored outside), put on the to do list.

Life goes on, I cut the lawn a few times and have cycled through 3 or 4 tanks of gas. Go to start it a week or two ago and it starts, no problem, I go to mow, 5 or 10 minutes in it stalls. Go to pull to restart and best I can do is get it to turn over and immediately stall. Remove air filter try to start, no improvement (starts and stalls), new spark plug try to start (starts and stalls). At this point figure time to clean the carb, or something is causing it to not get gas. I remove and disassemble, brake cleaner/carb cleaner everything and reassemble. Pull to start, it starts and stalls. Ok, frustrated, do something else and come back an hour or so later. About to show my lack of knowledge of more troubleshooting from here...

I think to myself, wonder if the handle being slightly wrong is causing the wire that controls the choke to not fully pull and do its thing. Pull the handle and place a small wooden block where the choke wire moves/attached to the engine to keep it pulled "a little bit more". Starts right up. Okay, I mow and consume the entire tank, but still have a little bit left to mow. Take a break, grab some water, refill the tank, turns over and stalls, try the block, turns over and stalls.

Most advice online for the usual suspects stops at the carb cleaning. So wondering what to check/do next?

Pictures to give an idea of what model I'm working with, it is a no prime/self prime start.
View attachment 165518View attachment 165519

I had something almost exactly like this happen to my yard machines push mower. New filter cleaned the carb etc with no luck. Many of these have a "starter jet" but it's tiny some don't. Essentially the retired guy who repaired it said that you have to go to a welding shop and get a tip cleaning tool. My fuel pick up tube had become blocked.

 

[tmorris1]

I had

I had something almost exactly like this happen to my yard machines push mower. New filter cleaned the carb etc with no luck. Many of these have a "starter jet" but it's tiny some don't. Essentially the retired guy who repaired it said that you have to go to a welding shop and get a tip cleaning tool. My fuel pick up tube had become blocked.

Strip back some stranded copper wire and use the individual strands that are very small. They work good for cleaning small carb jets.

 

[joekingcorvette]

My mom's lawn mower had a problem with not getting gas. I bought a new tank with a carb and extra primer bulbs and a spark plug for about $20.00. It took a few minutes to replace everything. If it's the carb just buy a new one from E-bay or Amazon or your local store. It's not worth trying to clean and fix an old lawn mower carb or gas tank.

 

[joekingcorvette]

Another trick if you want to clean the tank. Fill it up with solvent and grab some rocks and shake the crap out of it. Rinse it out and fill it up with gas. My dad taught me that old trick 60 years ago.

 

[wag123]

Strip back some stranded copper wire and use the individual strands that are very small. They work good for cleaning small carb jets.

Copper wire is too soft, too weak, and too flexible for this kind of job. You need a very thin steel wire for this. The best wire I have found for this job is the steel wire inside of twist ties. Just strip the plastic or paper off of it. The best parts about this wire are that it is the right thickness, it is strong, it is stiff, it is plentiful, and it is free.
To the OP, you have something plugging the main jet. You're going to have to poke a wire through it.