Question About BRRRR

[Matthew John]

Hey guys - I'm in the process of finding my first deal & confused a bit by the numbers. 

Let's use this example....

I buy a house for 140k that needs about 10k worth of work. I spend 150k total. 

My monthly mortgage is $900. 

I fix up the house, get it rented for $1500/m and I'm starting to cash flow. 

Now I want to move onto the Refinance part to pull out some equity and move onto property #2. 

The house now appraises for 200k and they give me back 50k during the cash out refinance. 

Here's where I have some questions...

1) Does my mortgage payment now increase from the original $900 since it's now worth more?

2) Should I be calculating my numbers off the ARV value?

Thanks for the help!