Stuck in ft Lauderdale with engine problems

[morgan342]

My yanmar 1 cylinder 12hp diesel died twice on me while under load. It starts up and I tested it on anchor. As soon as I get in the channel the engine slowly dies off. I just ran it and im getting black smoke with an odor and it died again. It wont start up right after it dies.
I am getting some white smoke out of my mixing elbow and I notice a little cut in my fuel line but it didn't go all the way thru.
What ive done:
1. Replaced fuel line that was damaged
2. Replaced both fuel filters
3. Tightened and rigged mixing elbow as good as I can get it.
4. Tightened all clamps
5. Checked fuel. No water, looks good
6. Checked oil, looks good.
Im in lake Sylvia, fort Lauderdale. I just need to motor to Biscayne bay where im stay for a bit to get some other boat work done. I rigged up my dinghy so if the engine dies I can jump in it immediately to tow it. If the engine doesn't work im not sure what to do next. I did everything I can think of. I just need to go 30miles.
All advice helps
Thank you