Turning to the other ideas in LWJ's note ...

LWJ has suggested the 1770 John could be the one who married Ann Cannell 9 Aug 1795. Sue has added that she was underage at marriage and was buried 28 Jul 1797, no issue.

It could be that this John Looney then married Ann Corteen 6 Oct 1797. Ann was buried 12 Mar 1809 (look carefully at Ann's parents Catharine Corteen als Stole 1809 will [John Looney is one of the people called to appear] and John Corteen 1814 [mentions 2 Looney grandchildren] on the will site).

The 1841 census has this family:
1841 census at Kirk Maughold Street, Maughold 1464 55 8 pg 9
John LOONEY 70 Fisherman Y
Eleanor LOONEY 55 Y
John LOONEY 20 Seaman Y
James LOONEY 15 Fisherman Y
>Thomas KENNISH 55 Wood Turner [? hard to make out] Y
Margt KENNISH 50 Y
Cath KENNISH 12
Mary KENNISH 9 Y

The above John's age 70 suggests a birthdate ca 1770. John Looney married Eleanor Corteen 5 Apr 1809 Braddan (this is just 4 weeks after Ann Looney als Corteen was buried, which seems too soon to be the same person ... or is it?). I counted 9 children baptized Maughold from this couple.

The other analysis says this can't be the son of Daniel Looney & Isabel Cashin b 1770, because he has to be dead by 1825. The IGI has a bapt for a John Looney 22 Nov 1770 St Matthews Douglas, s/o John Looney & Elinor Voughten or Murphy. He may be the person matching the 1841 census.