Should I selling my single-family rental or refinance it?

[Leewood Chan]

I have a single-family rental which I bought last year. It is paid $1300/month, and mortgage with escrow is $633.42 which is a good cash flow for me. I check my real estate agent. He said my house could sell for $210-220K for current market. I only own 85K to mortgage loan.

I would like to buy the quadraplex with asking price 675K; but I am going to offer for 600K, and I need to put 150K (25%) as down payment to get 3.5% interest.
I currently have only 60K cash, so I need 90K to make it for down payment. Here are my two idea that i can think of.

1. Selling my single-family, which should give me 100K or more after paid all the fee.

2. Refinance my single-family, then take out the house appreciation which should give me 66-70K. I got this idea after watch video about BRRRR. so I am not sure if it work or not, please me correct. I will also sell my stock to make 150K for down payment.

I am not sure which one is the better option, I would like to keep my single-family because it is my first rental property.

Please let me if you have any different idea because this is kind of new to me.

Thank you.