My 26bv blower vac starts and runs fine but shuts off after between 1 and 3 minutes. It will usually start again immediatly but then shuts off again. Any idead what the problem is? I have adjusted the carburetor because previously it would only run on half choke. Now it runs fine but won't stay running as described above. What are the factory settings for the carb?

dirty fuel filter & or fuel tank

Sounds like a lean condition. Rebuild carb, replace fuel lines and fuel filter and you should be ready to blow the leaves.

The parts inside the carburetor need to be replaced (gasket and diaphragm kit) and/or the L and H screws need to be adjusted on the carb. Try grasping and turning the L mixture screw on the carburetor (one closest to engine) about 1/8 to 1/4 of a turn counterclockwise.

It could be something as simple as adjusting the carburetor. (if you have the adjusting tool) otherwise it sounds like there may be some debris in the carburetor. After running for a little while, it blocks the fuel jet. Then when you shut it off, it falls back somewhere in the carburetor. I'd suggest cleaning the carburetor and draining the fuel out and putting new gas in.

Have you tried choking it about half way and see if that helps? Does it do the same after it is warmed up?

mass air flow sensor, or idle control valve.

Could be a defective thermostat in the plenum.
When a gas furnace shuts down the fan(blower) will run until the plenum cools to the safe range. Usually 1 and 1/2 minutes.
Intermittent operation is a defective thermostat or relay.

Sounds like faulty Crank position sensor. These tend to go out alot on Jeeps. Most of the time it will be running fine and then it will shut off like someone shut the key off. Hope this helps.

Seems to me you have a faulty cold control. (behind the temp control).Not too expensive , about 40 bucks.