To be honest with you, I don't think owner financing is ever a good deal. You most likely could find someone to do the owner financing with the amount you are willing to put down, but there is no way they will want to be competitive with today's interest rates. Most seller carrybacks I have seen have a rate of at least 7% or higher. I think one time I saw one at 6.5%, but that is very rare.
But there are some other strong disadvantages to doing owner financing. First of all, you are severely limiting your options on what properties are available to you, because with how hot the market is right now, there are not a lot of sellers that need to do this kind of financing. But secondly, there is usually a balloon payment in a fairly short term, where the new owner would typically try to refinance once they are able to do so. But what if your situation changes, and you can not refinance or do the balloon payment? I am just guessing the the old owner would be licking their chops to be able to foreclose on you, keep your 25% down, and all the payments you have made, and then turn around and sell the property to someone else.
However, if you really need a carryback, and you are convinced that it is right for you, feel free to contact me and let me know what kind of property you are looking for, and I will see what properties might be available.