Super h carb mystery

So let"s start a year ago the tractor was running then started smoking and died. I tried to get started but would not, I then found that when I took the intake off the carb the gas was running straight through. I took the carb apart a dozen times and could not find any problems I even tried a new float. The last time I took it apart I did nothing and put back together and it was magically fixed and ran all summer. So a month ago got back out of the shed and fired right up headed to town and made a couple miles and it died but would start and run on full choke. Did some road side repairs like clean filter checked have good flow and the tap on carb trick,nothing seamed to fix. So got started and thought will try on full choke made it 1/2 mile and smoke started billowing out of it I pushed the choke in and it ran great the next 7miles. When I got to town let set for a while and started back up so I put it away in the garage. So yesterday I got it out to take to tire shop let run in drive for 5 min then headed to tire shop made it 3 blocks and it died. Started and ran un full choke for 2 blocks and died. Started back up with no choke and ran great. Got the tire fixed and drove home had running in the drive and it died did the same thing. Let set for 5 hours and tired again ran great drove a couple miles. Getting really frustrated about ready to put on a m carb I have and try it. Any ideas???? Thank you in advance

Probably some trash in the fuel tank that covers and uncovers the inlet to the sediment bowl. When it is low on gas, drain it out and flush the tank to prevent a repeat. Water in the fuel used to be a problem, but ethanol in the fuel has eliminated that factor (unless there is a dramatic amount of water. Jim

That double float needs a bit of "tweaking". There is not a lot of clearance between the floats and the fuel bowl, and if the floats are not exactly centered in the individual fuel bowls, the float will make contact with either the inside or outside of the bowls. It'll drive you nuts until you get it right. I also bought a new float one time to cure the same problem, only to learn the new float wasn't any better.

i had the same trouble with my super h once too. it would run for awhile and then stall out , if i had the chock out it would run for awhile again and then start to flood. gas would run out of the carb when it wasnt running sometimes also. i had just rebuilt the tractor from the ground up and everything was new, except the float, tried a new one , same thing. someone then told me that the new gaskets dont always fit right and to check the inside clearance between the float and gasket , i exacto knifed the inside of the gasket in the bowl and put it together and its ran perfect ever since. just something else to check

Hey AJ, Have you givin any thought that it might be electricial. sounds like points are getting hott and breaking down. Points dont need but around 8 volts going to them. reason i say this is because this same kinda deal baffled me for a week on my 135 that i had just totally rebuilt. I kept thinking it was running out of gas took the carb off and apart several times. and it acted like it was running out of gas. How i found it was i put a timming light on the spark plug wire and saw that it was actually electricial and i noticed the plastic on the points was a little melted...just something to consider.....a resister on the coil fixed me right up

rustyfarmall might have it, the float touching the insides can be critical. Might Dremel the insides of the chamber, and be extra careful in positioning that float.

I had a similar scenario. Ended up being a plugged vent in the gas cap. I chased that for several months before I heard the air sucking sound when I removed the gas cap. The plugged vent was creating a vacuum and stopping fuel flow. Choking would increase suction and over come the vacuum for a little while.

No way it's electrical.

It wouldn't run any better with choke, or start billowing black smoke (out the exhaust anyway).

The float is hanging up on the side of the bowl. I had the same problem. Mine would usually hang up at the top.

We took the carburetor apart half a dozen times, blindly tweaking things until it stopped doing it.

I *HATE* that M carburetor design. If you're a fraction of a millimeter off, the float hangs up and gives you fits!