Honda 7.5 hp problems.

I have a mid 80's honda 7.5 hp 4 stroke that came with a boat I recently bought. I ran it one day and seemed to run ok. Went to run it again and wouldn't start. So I replaced fuel line and tank. Couldn't find connector locally so I used the old one. Cleaned carb and nothing. I changed plugs bc they were pretty black. It started right up. I went ahead and changed the oil and lower unit grease. I ran it in trash can of water for several days. Seemed to idle well. When I pulled it out of trash can there was a black ring around lower unit where water line was. Didnt think much about it. Took boat out. Ran really good for a while. Then randomly died. I got it start right back up. This happened about 10 times. Would run 5-10 min then die. Decided to load but up. Headed to boat dock it died again I relized I had ran it a few min with choke on. Couldnt get it to start again and noticed a lot of black stuff in water. I got it going again but would only run if choke was on. The last 100 yards to dock I had to start it several times and couldn't keep it running. When I got home I checked oil and seemed like it could have been a bit running but wasnt sure. Does anyone have any idea what the problem could be? I would really appreciate the help. Thanks.

"Only run with the choke on". That means your carb jets are plugged.

I got carb cleaned actually did it twice. Motor will run for 20 min or so then die. I'm losing pressure in my fuel line bulb. I pump it and starts right back up. I ran it for about 2 hours today with restarting several times. I believe I'm getting gas into my oil. Next step is compression test unless someone knows something I haven't thought of? My spark plugs are getting pretty black.