1985 Johnson 150 running poor

[jasoncooperpcola]

The family i sold my 83 V20 to asked me to come over today to look at the boat. Keep in mind throughout all this the boat is in the water, no dock, in 40 degree water and i had to wade out to it. The motor would not crank tilt, etc. It was dead. Well after 2 hours of fooling with it i found the stripped bolt that was the main ground off the batterry. I tightened it and she came to life. They asked me if i could load it on the trailer and take it back to their house. I agreed and went with one of them on the boat. Halfway to the ramp she died. This time she would turn over but would run about 2 seconds and shut off. After another hour of fooling with it, this time without tools, i found four loose spark plugs. They were literrally loose i unscrewed them by hand. I tightened them with a pair of slip pliers. She cranked back up and we almost made it to the ramp and it died again. After twenty minutes of paddling we were back on dry land. I told them to replace the plugs and TIGHTEN them. My question is this, were the loose plugs the whole problem or is there an underlying problem? Also the tach is not working does anyone have any suggestions? Also the boat is for sale if anyone is interested.