Many thanks to Sandra, Sue and Barbara for their help and advice. I agree that it looks as though James Watt was not a Manxman. As you will see Sue he was a painter as shown on later certs. I will check Scotlands People for a marriage he had died by 1890. I cannot find a death cert in Scotland. The problem is that james Gilmour is a very common name in Scotland so if Watt is missing I am snookered. I have been searching for this man for over 30 yrs.
I have the following info. that I am posting just for people's interest

1865 Death cert Greenock Renfrew
James Thomas Watt Gilmour at 20, A?? street Greenock 9 months parents James Watt Gilmour ship carpenter and Julia nee Martin. Father J W Gilmour present.

8 Oct 1865 Birth James Albert Gilmour at 10 Bruce St. Greenock son of James?all/?att Gilmour (ship carpenter) and Julia nee Martin married Jun 16 1863 Kirkmaughold Isle of Man

1866 death in the West Parish of Greenock Renfrew
24 May 1h. 20. At 10 Bruce Street Greenock Julia Gilmour 22 yrs. married to James Watt Gilmour Shipwright (journeyman).Parents Allen Martin (painter journeyman) and Christan Cannell. James Watt Gilmour widower present.

20 Mar 1890 at 32 Richmond St, Glasgow
James Albert Gilmour 24 yrs (glazier master) of 711 Gallowgate Glasgow and Isabella Elsie Sutherland 22 yrs of 32 Richmond Glasgow
Parents James Watt Gilmour (ship carpenter journeyman) deceased and Julia nee Martin deceased
Donald Sutherland (joiner master) and Elsie nee Cruickshank deceased

Regards to all
Susan