My srm3800 runs but when itry to use it it seems to cut off like not geting fuel it idle go but it will cut off aftet I give it gas

Check there are no kinks in fuel line.
Make sure that the air filter isn't blocked.
Check the throttle cable is operating the throttle plate in the carburettor ok.
Ensure chain isn't too tight.
The carburettor should be a tight fit on the air inlet manifold.
It's possible that some of the jets could be blocked in the carburettor. You can try and clean these with compressed air but ensure you remove any seals gaskets, springs on the diaphragm pump , primer bulb etc as they can be damaged by the pressure.
If the the choke normally disengages when the throttle trigger is squeezed, check this is working ok.