Well, if your choke isn't closing it certainly won't start unless you give it some external fuel like you did before. However, even if the joke isn't working properly once you get it started with external fuel it should stay running on its own no problem. Otherwise you have a restricted or at least partially restricted jet or jets in your carburetor.
The most interesting part of your post I saw was the fact that you said you overhauled an engine at 140 hours.
Do you mean the entire engine or just the carburetor? The only way one of these should possibly need an overhaul and only 140 hours is if it was one of the very first gen Briggs v-twins that had the yellow typically or the other air filter cover that had a clip or clips holding it on.
That thing was known to bypass the air filter and let dirt go down the D shaped hole into the intake and they were wiping out the rings at under 100 hours.
It's funny how this happened a lot on the twins without proper air filtration but the singles can run for years even with no air filter on them and not suffer a similar problem!
They changed it once and then they changed it again but you always want to inspect these air filters and the D shaped hole that's actually the intake to make sure there's no tan colored, dust or dirt going down in there. It's usually pretty obvious when it happens. If you ever see that you must fix the air filter housing immediately even if you have to put some weather stripping in there so it seals up or even if you have to use some RTV to literally glue your air filter on both sides so it can't slip around and go down the intake.
With exception of this occurrence which happened way back with the early design when these were new and most all have been fixed or junked by now, even though people love to be Briggs & Stratton detractors and haters, these engines can and do run a long time and many, many more hours than that.
Actually, typically the machine falls apart around them and they are scrapped for the need of a simple repair or for a no start but I have seen a good handful of these with 800, 900, and 1200 hours.
Most of them get discarded with the machine they're on under 400 and many between 200 and 300 but those engines have tons of life left in them.
The engines do have a problem with push rods bending and that's usually cause from valve guides slipping due to being overheated because no one has pulled the shroud off and removed all the debris, nesting material, grass, or grease and grime from the cooling fins on one of the heads.
You must always keep these full of oil too. I prefer to keep them at the full mark at a minimum and actually prefer to keep them about a 16th to even 1/8 of an inch above the full mark. These things will snap around in a heartbeat when they get down slightly below the add mark.
The most interesting part of your post I saw was the fact that you said you overhauled an engine at 140 hours.
Do you mean the entire engine or just the carburetor? The only way one of these should possibly need an overhaul and only 140 hours is if it was one of the very first gen Briggs v-twins that had the yellow typically or the other air filter cover that had a clip or clips holding it on.
That thing was known to bypass the air filter and let dirt go down the D shaped hole into the intake and they were wiping out the rings at under 100 hours.
It's funny how this happened a lot on the twins without proper air filtration but the singles can run for years even with no air filter on them and not suffer a similar problem!
They changed it once and then they changed it again but you always want to inspect these air filters and the D shaped hole that's actually the intake to make sure there's no tan colored, dust or dirt going down in there. It's usually pretty obvious when it happens. If you ever see that you must fix the air filter housing immediately even if you have to put some weather stripping in there so it seals up or even if you have to use some RTV to literally glue your air filter on both sides so it can't slip around and go down the intake.
With exception of this occurrence which happened way back with the early design when these were new and most all have been fixed or junked by now, even though people love to be Briggs & Stratton detractors and haters, these engines can and do run a long time and many, many more hours than that.
Actually, typically the machine falls apart around them and they are scrapped for the need of a simple repair or for a no start but I have seen a good handful of these with 800, 900, and 1200 hours.
Most of them get discarded with the machine they're on under 400 and many between 200 and 300 but those engines have tons of life left in them.
The engines do have a problem with push rods bending and that's usually cause from valve guides slipping due to being overheated because no one has pulled the shroud off and removed all the debris, nesting material, grass, or grease and grime from the cooling fins on one of the heads.
You must always keep these full of oil too. I prefer to keep them at the full mark at a minimum and actually prefer to keep them about a 16th to even 1/8 of an inch above the full mark. These things will snap around in a heartbeat when they get down slightly below the add mark.