Send delimited data from files using File.PassthroughService and TCP.Framed.PassthroughOperation

I'm new user learning to use Iris and Ensemble. I'm trying to set up a TCP interface to send delimited data from Ensemble to another interface engine. I created File.PassthroughService to pick up the file and send the data to TCP.Framed.PassthroughOperation. The framing is MLLP and SSL configuration used. It is able to process small files around 50kb. When I drop a larger file such as 5mb, the operation is not getting the ack within the 60 sec timeout. After a couple retries it exceed the failure timeout, the message is put in error status but then the file service will create another message and send it through successfully. 

Does anyone have experience using pass through service/operation to send delimited data through TCP. If we want to send data up to 100mb, any tips on what configuration setting I should use to send the data through without numerous retries.