Trimmer will start when on choke but will not keep running,unit is brand new

clogged high speed jet

It sounds like a carb problem. You can buy a rebuild kit on line for cheap and rebuild it.Should run fine then.

You have a few possibilities. Make sure you have good fresh gas in the tank. You're not getting enough gas, so choking helps get more gas than air, making it run better. Could be the carb diaphram (not very expensive if you replace yourself), when they get old they don't perform like they should. Could be the filter in the gas tank is bad, plugged. Also might be just an easy adjustment on the carb Low, and High speed screws. The choke has three positions, full choke, partial choke, and no choke, which means run position.

It is unusual for a trimmer to flood itself. It is common to have a lean condition diagnosed as rich.
So lets start by seeing if its lean or rich. Get unit running and apply as much throttle as possible and keep unit running then slowly close the choke. If unit starts to run better as choke is closed then it is lean. If unit dies immediately and is hard to start again it may be flooded.
4 possible reasons for flooding...
1. piece of debris in inlet needle, needle lever adjusted too high
2. adjustment screwd turned too far out
3. exhaust screen clogged
4. low compression
If unit has a stuck inlet needle it will flood while engine is off and be very difficult to start- remove fuel source and/or turn adjustment screws all the way in and pull rope until unit starts ( 4 or 5 times)
clean the carb, screws should start at 1 and 1/2 turns out on the low and 1 turn out on the high.
clean the screen.
If the unit has low compression it is not worth repairing- the cost of repair will exceed the cost of replacement.

Agreed all these cheap trimmers are built at a price the only way to tune them is to take it to the dealer, The special tool costs nearly as much as the machine.
So most machines under 100 dollars are throw away and replace its bs but everything is ending up the same.

Are you saying that this is a brand new trimmer or is it new to you, used trimmer? You are describing a problem that is typical of a used trimmer.

This is a sign of a clogged gas cap. When the gas cap can't breathe, it chokes out the carburetor.

Try this: The next time you run the trimmer, and it starts to die, loosen the gas cap, it should start running again.

Jim

Jets in carb are dirty. Take carb off and clean, blow out all jets, you may have to use thin wire to get all gunk out. Also fuel line might be dry rotted. Put carb back on and adjust settings on carb.

You need to disassemble the carb. and spray with carb. cleaner. If you need tips on how to do this, just let me know. You may need a new carb. kit as well, but we won't know that until you first perform the first step, or if the carb. parts are more than 3 years old. If they are, then go ahead and buy the carb. kit and replace the parts.

Jim

purchased new unit

Many times with a gas mix, after sitting for a while, the mix separates and gums up the carb. Taking the carb off and soaking it overnight in a parts or carb cleaner and running carb cleaner through the tank and gas lines will cure this.