75hp mariner need help with year

[Tommy Randolph]

need help with my motor starts up then shuts off when key released

 

[Tommy Randolph]

serial #a170335

 

[galamb]

It's a (late) 1985 model.

For the 1986 model year Merc redesigned many of their models AND changed the serials (production numbers) from all numbers (1234567) to an alpha numeric (0A123456) - there is always a "zero" in front of the letter in the earlier models although it's often omitted.

Towards the end of the 85 model year they started using the new serials but they almost never show up on the parts lists as a "valid" number.

As to your issue - it's dying as soon as you stop choking it? - clogged carb(s) would be the top of the suspect list.