Cash out refinance will turn cash flow negative?

[Douglas Goldstein]

I'm looking for ways to finance my next purchase. I'm could do a cash-out refinance on a rental I own since the LTV is 57%. Currently, it has $150/month cash flow. If I refinanced to an 80% LTV, I could get $180,000 to spend, but at that maximum level the cash flow would plummet to an $850/month loss. I wouldn't do THAT much, but how low would you let your cash flow go in order to unlock home equity for a new purchase?