I'm not sure if I'm answering your question correctly, but I think, in short, the answer is "maybe". Yes, you can be approved for a second mortgage for an investment property based on many factors. Your best bet is to contact a mortgage broker at your bank, credit union or contact a Realtor in your area who can provide you with some guidance and references to mortgage brokers. Many of our offices have mortgage brokers colocated as well.
If you're looking in the Northern VA, Maryland or DC area, I can help you there. I recently purchased a 2nd home as an investment property and was required to put at least 25% down. Whether or not you're approved for the loan is based on numerous factors such as income, credit score, debt, etc. Too many for me to list and a mortgage professional would be more qualified to answer that question anyway.
But, one thing to note is that you can write off the interest on your taxes on your first 2 mortgages. So, if you only have one mortgage on your first property, you should be in great shape for the second as well. Here's where an accountant would come in handy as well, but you can also write off depreciation on appliances, etc in your rental property.
Anyhow, hope that helped. If you need anything at all or want some clarification, lemme know.