I thought the rating feature is not the reason of affecting the reviews. Before you uploading your app in app stores, you have to check your app on different mobiles so that you can know the targeted types of mobile phone and users. Sorry I can't help you solve this problem with details, but I will recommended you some tips to get more positive reviews(by the way, I suggest you design a rating feature for it will give you more chance to get app installs):
Create a user community
You can create a user community to motivate them to leave their feedback, because they can find more partner who have same interests in this platform and have more impetus to leave their reviews.
Incentivize users to leave feedback
Now, most people not prefer to leave their response for the reason they think it is not necessary to do. Therefore, you can incentivize users to leave their feedback. For example, you can make use of the method of IAP and offer wall to motivate them to leave their review.
Cater to the interests of users
If you let your users leave their feedback directly, they would feel impatient and have conflict psychology. So you can guide users to leave their review when they feel happy. For instance, if you are an app developer of game, you could make users to leave their feedback when they have won a game.
cooperate with a professional company
If you have enough budget, you could buy app reviews form a paid-review company(bestreviewapp) to help you, which can provide more professional services and tips for you to get a higher rank in app stores.
invite your friends to leave feedback
this is a free and useful method to get more reviews from your app, you can try it if you have limited budget.
I hope these methods will be useful.