2 seller financing multi-units

[Jean M.]

Im interested in 2 two family homes in glens falls ny. The seller is a landlord who is looking to retire and is willing to hold a note on the 2properties. He wants $135,000 each with 10% down and 4.25% interest for 30years. Neither home needs workThey both gross $1600 per month each both have $3700 tax and $1263 insurance. The sewer/garbage/snow removal is estimated at $140 per month on each property. I ran some numbers and offered him $100,000. He says his price ia firm. 

Can anyone tell me if this is a deal i should look into or should i drop it and move on. Im new to investing and don't want to over analyze but i also dont want to have negative cashflow.