Without experience and advanced planning it could be a net negative, PM nightmare, or combination of challenges. 

Or maybe you want to do a combination of the above?

Echoing what @Devin Peterson said... unless you put a lot down, purchased below market, renovations substantially increased value, or better yet a combination of all that he wouldn't have enough equity to refinance.

Invest in upgrades that enhance the property's appeal to long-term tenants, such as modern light fixtures, fresh paint, or energy-efficient appliances .

If there is 5-6 units, possibly some could be combine and it would still be good for an FHA/conventional buyer. 

HELOC is my first thought too but I am looking to combine them all into one mortgage and take a HELOC out on all 4 of my houses because they are just typical oklahoma town houses that only run in the range of probably 50k. 

Both of these combined cannot exceed the total of $69k/$76,500, however that entire amount can come from the employer side if you don't contribute on the employee side.   

Judicious use of refinances combined with 1031 exchanges will have you cooking with gasoline in no time.

Hi Caleb,Is the rent of $1,300 a month per unit or combined?

@Manny Martinez FHA monthly mortgage insurance is typically 0.85% of the loan amount, so you are effectively already paying the rate you were quoted, $200 per month on an $80,000 loan amount would be about the equivalent of a 3% interest only loan, now factor in the difficulty in finding a 2nd mortgage in todays rate environment that low and assuming the refi rate you are talking about is a fixed rate, your $200 extra per month is paying down the balance of the $80k further reducing the effective rate you are paying on the $80k, all while paying about the same effective rate on your existing balance when you combine your rate and MMI... seems like it is a good move to me or at least better than finding a 2nd mortgage.