i got a few questions about my lawn mower?

No 10w30 oil is not okay. Most lawn mowers use 30 wight non-detergent oil which is specifically for those types of engines. I'm not sure how often you do maintenance on your mower. I hope you clean and gap the sparkplug at least 2 a year but its better to replace it every other season. As far as the air filter you need to take it out and clean it at least twice a year as well. Just make sure you clean it the right way with liquid detergent and warm water and make sure it is dry before you re-install it.

There could be a number of reasons why it runs for that long and then stops but without inspecting it I cant really say. It could be something as simple as a loose wire near or around the bagger discharge area than when you start out across the yard the vibration of the mower causes the wire to short. If you cant seem to trace it down just take it in to someone you trust and have them have a look at it and not just tell them to fix it but to give you an idea of how much it will cost you to fix it first. Hope this helps

First, most engine makers recommend 30wt oil, the 10w30 probably won't hurt it but it may use more oil when it is hot. About the air filter, some have a foam prefilter on them that can be washed and reused. Others don't and are made of paper that can not be washed. Now about the running issue. It sounds to me like the carburetor needs to be cleaned. It should be taken off and disassembled. Soak it in a good carburetor/parts cleaner, blow it out with compressed air, inspect and clean all passages and put it back together with a rebuild kit. Also check the fuel tank for dirt and water. New fresh gas is a must.