1977 70h.p. johnson seahorse need help

I know this may be a little lenghty but I want to give as much info as possible. Me and my father went to the lake about a month ago. Our Johnson started right off and ran great. We idled through the no wake zone, and found a nice spot to fish. after about an hour of sitting and not running I attaempted to start the boat. The starter seemed to turn for a second or two and then kick out as if power had been cut , or as if it were getting hot. We ended up paddling the boat back to the dock, over 1.5 miles. When we got back I thought it would be ironic if the boat would start and it did. on the next trip I went to the same area right off of the trailer the motor started and ran perfect. I again found a nice fishing spot and idled past the no wake zone. Once the boat had set for a little while as I fished I started the boat idled out of the no wake zone and leaned forward on the throttle. It spuddered and missed, then after letting it run like that for about 2 minutes it picked up rpms slowley and ran fine again. on subsequent trips I found that by fooling around with the electric trim sometimes it quickens the pace that the rpm pick up. or maybe it's my imaginiation. I have replaced the spark plugs after the first incident they were pretty heavily coated. I then checked them after the second incident again they were pertty heavily covered. There are no marine shops close by hear in west virginia can someone please help and give me and idea of what to do.

Re: 1977 70h.p. johnson seahorse need help

Also I meant to include in the post the starter issue has not occured again, also where "for a lack of better marine knowledge" where is the pee hole located on my motor. It is a 1977 70 H.P. Johnson Seahorse. It is all white with the orange decals. I have read many post in this forum when I first got my boat to help with startup and checking certain parts as well as rebuilding the motor remote control I would like to thank all of you for you help so far. But please help before I go nuts and sell my favorite boat.