Not in TD status. TD permits presence and study but not employment, and small-engine repair is not a listed profession, so he cannot obtain TN in his own right on that basis.
A trade that is not listed has no TN of its own
Hypothetical example: the spouse of a Frontenac Islands instructor runs a marine-engine repair service from a shop beside the house and assumes he can pick up similar work near the college. TD status, which he would hold as her spouse, does not authorize employment of any kind, including self-employment and cash work. TN is not available to him because mechanical trades are not on the USMCA list, and no amount of experience substitutes for a listing.
His lawful options are to keep the island shop and return for the season, to study in the United States in TD status, or to seek a different category of his own if a U.S. employer would sponsor one, which for a trade is uncommon. If he holds a college diploma in a listed field, that changes the analysis and should be checked.
The household should settle his plan before he tells customers he is leaving. Hypothetical example: A Frontenac Islands theatre professor plans to relocate with a spouse who operates a small bookbinding business. The spouse may accompany her in TD status but must not run that business or take paid work while present in the country.
Their first household decision is whether the spouse will remain in Canada to manage clients, study, or qualify independently. A calendar showing where work will occur prevents a well-meant move from becoming unauthorized employment.