Mower starts but wont keep going.it has petrol and oil,it had carberetta serviced last year.

clean the spark plug
drain the water out of the float bowl
take it in for a service

Either:
1. If it's a two-stroke the oil/petrol(gas) mixture could be wrong. if you mixed it last year or left it in the tank, the petrol (gas) will evaporate leaving the oil behind making it too oily and fouling the plug.

2. The mixture is too rich - the plug will be sooty and smell of petrol. Check carburettor adjustment and float height.

3. There is lubricating oil entering the cylinder, either worn or broken piston rings or (four strokes only) worn valve guides

feed line blocked from petrol tank test to see if petrol is coming through , replace feed pipe also check carb float chamber needle could be bent thats why its not drawing petrol through hope this helps

It will run for a few minutes and then shut down?
Lets ignore the growl for now. Loosen Gas cap and see if it will keep running. The rattle might be in the pull cord mechanism..possibly not related to stalling issue

What is the make/model/year/motor etc.?

only other thing i can think of is has the air to petrol screw been moved

Check the fuel...most often stale fuel creates havoc...YOU MUST FLUSH THE TANK donot add to old crumby gas, YOU MUST clean out the carb(remove the fuel bowl and carb spray all the tiny openings,orifices, check the air filter, check the oil, Add NEW fresh fuel, and hit with a quick spray of starting fluid just prior to restarting...should run out well.

try replacing the carby diagphragm. they harden with age. and also check the main jet to see if its plugged with old dryed up petrol

Use starting fluid when it does finally start continue starting until all the oil is cleared out of the carburator you may need to repeatedly choke out the carb with the engine running to clear out the carb, do this by removing the air cleaner, start the mower on high speed rpm, and cover the air intake with your hand repeating this start/ choke/ stall procedure until it is cleared out it works, I just did this to a mower last week that had too much oil in it, the mower smoked quite a bit but eventually returned to normal

Check air filter, check screen in bottom of fuel tank,
New spark plug and also check the spark.
If there is a weak spark, the coil may need to be replaced.

If you have good spark, clean air filter, and clean fuel tank screen, then the carberator will need to be pulled of and cleaned out with solvent