I am sorry for your troubles whatever they are. I truly am. I will pray for peace for you.
Now, as far as price goes, it will be difficult to sell at a premium due to engine problems. It could be a $200 fix or a $10,000 fix and the buyer does not know. You hope it is $200 and the buyer will assume $10,000. I would highly recommend you get it fixed and sell it as a solid motor. If you are with 4 hours of Greenville, SC you need to get it to Don Weed at European Marine. He has amazing diagnostic abilities. He only works on Mercury motors.
Price will also vary with the age of your electronics and trolling motor type. Other accessories like a hydraulic plate, power poles etc do not add a ton of value. Generally 1/3 to 1/2 of what they cost. It sucks but that is the way it is.
You have two options, let it go for a big discount without fixing the motor or pay to have it fixed and get a better price. In either case, clean up the boat, take GOOD pictures and be ready to sell by getting paperwork ready. Write down the motor, boat and trailer serial numbers so a serious buyer can do their research.