In the true sense, no, there weren't really teams as you'd find at F1 or NASCAR auto races, at least at the Stock Outboard level. Stock outboard was the "entry level" boat racing and as such was open to the backyard builders. There was never much money in it. My Dad won $200-$400 for winning some marathons, and maybe a $200 for a closed course race - IF there was any prize money offered at all. In those days, that would cover your gas money for the weekend, and you might be able to buy a used motor with the leftover.
Some racers who lived near one another might band together to share a trailer or tow vehicle, forming a loosely defined team, but that was usually the extent of it. As you move up the ranks to the tunnel boats, offshore, unlimited hydroplanes, etc. there was more money involved and it was more common to have a team to get the boat on the water. It would be very difficult for one person to compete with an unlimited hydroplane...