Rock Star Real Estate Minute: Using Home Equity via Credit Lines for Investment Properties

I was one of those people asking about using a HELOC to purchase an investment property. Your “Real Estate Minute” was helpful. Here’s my situation. I own my principal residence. There is no mortgage on it. I have a HELOC on this property at 3%. I do not owe anything on it. I have no debt at all (and it feels nice). I only work part-time. So, qualifying for a mortgage on an investment property might be tricky. I’m thinking of using the HELOC for the entire purchase of the investment property thereby bypassing banks all together. The rental income will cover all carrying costs. My HELOC is $300k; my possible investment property purchase is $150k. So, do I use the HELOC to pay for the entire property or use half of it as a downpayment and try to get a mortgage on the other half on the inv. property?