It has a different engine than the ones we were referring to, the old Tecumseh.

Heck, it could just be a spark plug that heats up and dies. You will want to remove the air filter cover and ensure that the choke has opened. The main is in the stem of the carburetor where the bowl attaches I believe. I take and bend the straw from a carb spray can and shoot it up through the center of the stem to clean the main and tube before I have to pull them apart. I don't know these carburetors real well yet. One would assume that there is a bowl vent that is visible from the air filter side of things that could be plugged.

Sax , no the engine for the Model 20381 is the Kohler 149 cc 6.75 Net- Torgue Rated unit . Tom , The normal issue within these engines is fuel fouled carbs . This unit has a prefilter located within the fuel tank , as I described the main jet beside the float hing pin location on the emulsion tube or STEM as you describe has a metering rod with additional orifices. The Ops Statement if you read it carefully , you will see he states it started fine and began sputtering after 90 seconds. The Thermostatic Chokes on these units fail open . So starting would have been troublesome . They open completely after approx. 3 minutes of heat from the muffler box area. I have worked on over a dozen of this and Briggs with the same Bi-Metal Auto Coke System and yet to see one fail closed . However Never Say Never lol .Easy for him to remove the air canister cover and filter to determine that the choke plate is indeed open . My money is on the ( 6 ) orifices or prefilter on the gas line are the restriction of fuel that is causing him problems. P.S.The NGK BRN6NES Plug on these Kohler usually last 3-4 yrs with proper servicing , so he may require a fresh plug for optimium fuel efficiency . But should not affect the runability of the mower in his described manner .

Thanks to all of you for taking the time to reply and help. I appreciate it. Here is an update from yesterday before your replies. I drained all of the gas, sprayed carb cleaner in the places that seemed logical. I am not a mechanical person. I thought I would try to make sure the fuel line was clear between the tank and carb. The end of the line that attaches to the tank has what looks link a long thin filter that inserts into the bottom of the fuel tank. It looks clean to me. I put that back together. I put fresh gas back in.

I then started the mower, and thought the problem was solved. This time, the mower ran for five minutes before it started to sputter. It went on sputtering for about another 4 minutes or so before I shut it off. Had to go out yesterday after that, got back late. Read some comments here this morning. Sprayed around the carb as much as I could, put some carb cleaner spray in the tank. Waited a little bit. Started it up, and it ran fine this morning. Ran it for about 10 minutes. So, I hope it's really fixed. Thanks to everyone for your help!

1. Ok Mark , then the restriction was within the Prefilter as I thought . The waxy e-fuel gumming would have been missed by the untrained eye , it is easier to see within the float bowl as slightly opague to clear crystals or filmy fluid . The additional fuel cleaner you added to the tank overnight cleared any residual residue within the fuel circuits. These carbs do not tolerate ethanol fuel at all , believe me I repair them weekly . Have it down to approx. 30 minutes for a complete teardown and rebuild when warranted . I can usually identify the severity by just hearing the engine running . I had a similar stumble , minor miss when my Son refueled my fuel container without conditioner , after he borrowed my grass trimmer and chainsaw 3 yrs ago . I just added some Startron immediately to the fuel . Anyhow you may wish to replace the wimpy prefilter with a larger chainsaw or grass trimmer unit as I have which will better prevent future clogging issues . Anyhow ensure to treat your fuel in the future and probably should check you spark plug and air filter if they are over 3 yrs old also . A investment in optimium performance within the future . I love my Toro,s grass cutting performance , just raise my eyebrows at the Cheap Carb , although it does make me some pocket change repairing same lol , All The Best !

Hopefully you are getting ahead of the problem. Ewalk, these are the Loncin engine that Toro markets. AKA OEM Chonda. I've not had one yet that the carb had to come off. Color me lucky? :)

Tom : Your Singing to the Choir ! YES , I KNOW WHAT ENGINE DESIGN IT IS , I stated that ! I further have worked on every Toro lawnmower Engine Manufacturer ! Tec , Toro , Briggs , Kohler , Honda . The problem was as I said the Fuel Prefilter within the Tank most likely . Otherwise any one of the 6 small orifices within the carb internals .Nothing to do with the Auto Choke as you indicated , and very unlikely a faulty plug from the reported symtoms . You Really should take one of these carb compliant units apart before you speculate . Not Rocket Science , but very apparent once you see the evidence 1st hand . The longer the e-fuel sits untreated the further and more severe the damage moves within the carb unit . If you treat the fuel quick enough before more formation occurs and hardens then you do not have to disassemble the carb . I have a Toro , My son has a Toro , My Brother has a Toro , MY Neibours (4) Have a Toro ... Been There , Done That , Got The Picture ?

Geese, sorry Ewalk. In my copy of the paperwork it read Kohler, not Loncin. They may even come out of the same factory from what I know. One would assume the carbs have a similar design, maybe not through and through. The serviceability regarding parts is not the same though.I would think it has a main and a mixer like the rest. oh, and you forgot Suzuki and Kawasaki on your list.:)

Tom , the jest of my advice was specific to the Model in Question . Obviously the other Toro Models have similar features within their carbs and the same inherent problems . However and more specifically Toro has gone away from the Thermostatic Auto Choke Feature and gone back to the choke-less Primer /Purge Function , on many of their more expensive models.When I trouble shoot a no start or hesitation restriction issue I think worst case scenario . Why have to do the job twice and double bill a friend or customer . Sure I can advise carb cleaner in the fuel or replace the fuel filter or do that and inspect and thouroughly dissemble , inspect and clean all internal carb components properly within 30 minute procedure . I then most often inspect the plug and air filter and advise accordingly . I have seen enough Toros within the last 3-5 yrs to troubleshoot the problem within minutes. Also as for the Suzuki and Kawasaki Engine Line , I have owned and repaired numerous 500 cc Industrial Units , nothing within the smaller push mower realm . Rest assured after 10 yrs of Racing Snowmobiles and Motocross in my day , have Tuned and Repaired & Rebuilt a lot of Kawasaki , Suzuki and Yamahas along with JLO , Hirth , CCW , Sachs , Fugi , Starfire & Rotax 2-Strokes ! P.S. My 1st lawnmower repair was on a 3 .5 hp Clinton back in the early 1960's , Woops I just dated myself lol :)