If you are saying that the mower shuts off when you engage the blades (or put the lever for the blades in the up position) then the most common problem is a bad seat safety switch. This is located under the seat. It has two wires going to it.
More than likely you either have a bearing seized up in one of the deck spindles, a bent blade that is in a bind or debris on the underside of the deck keeping the blades from turning. If this is the first time it has been used in a long time, with the mower off, work the blades back and forth by hand until they move freely then start the mower and try to engage them. If they do not start to move freely then you will have to figure out which one is not turning and take it apart.
carb. adjustment, oil my need to be changer, air filter is dirty. fuel filter needs to be replaced
It is a small electrical thing on the bottom of the carburetor. It will have one or two wires going to it. It shuts the fuel from getting through the carburetor when the key is off.
Your mower has developed sentience. It is a member of METALT (Machines for the Ethical Treatment of Living Tissue) and refuses to harm a single blade of grass.
check fluid level in radiator
Most mowers unless electric have a lever that works as a throttle/choke to start your mower. If you just pull back on the lever till the throttle/choke no longer allows gas to the engine this usually shuts it off.
If the mower has a shift knob control for "Start" "Run" and 'Stop', the kill switch will be on the end of the cable that leads to the throttle bracket. If the mower has the safety handle that shuts off the mower when it is not depressed, the kill switch will be at the end of the cable that leads from the handle to the engine. If the mower is operated with an on-off ignition switch, the kill switch wire will be spliced to the switch "off" wire some where between the throttle cable and the switch.
Most new mowers have a cut off switch inside the oil filler tube that shuts it off when the oil gets to low.Seeing it is a new mower the oil will burn a little causing the shut off to activate,put some more oil in it and it should be ok.
I solved my own problem,my weed trimmer has a on and off switch the wire in the switch had a bare place that was shorting out, by lifting the trimmer I was putting pressure one the bad connection.
When the engine shuts off, remove the spark plug and unspect it. If there is fuel on the plug, the engine shuts off because of over flooding probably caused by a clogged air filter or faulty spark plug or may need a carburetor adjustment. If the spark plug is dry, the engine shuts off due to fuel starvation caused by a clogged fuel filter or may need carburetor adjustment.
Check your oil level in the engine. There is an oil level sensor that will shut the engine down if the oil level gets too low.
With a 10 amp charge about 1 hour if the battery is totally dead. You should really use an automatic battery charger that shuts off when the battery is fully charged to avoid overcharging.