need help with year identification

[mikel6227]

i have a classic fifty 45hp mercury serial number ob258479 can anyone tell me the year? i run the motor when it gets to higher rpm /mph the motor beeps until i back off the throttle has anyone else had this occur?

 

[QBhoy]

i have a classic fifty 45hp mercury serial number ob258479 can anyone tell me the year? i run the motor when it gets to higher rpm /mph the motor beeps until i back off the throttle has anyone else had this occur?

As far as I know. These engines ran from about early 80’s to late 80’s or just touching 90. Be somewhere around there. Depending on the decals on it. I’m not good with serial numbers and age. But I know roughly from the decal colours.
There aren’t many things that make these beep. And some early have no alarm at all, I’d suspect. I think all of these were pre mix oil in fuel things. So won’t be oil injection. The most likely suspect would be an overheat alarm. You may want to look at your impeller. If that’s ok..look at your engine height set up. It may be losing water pick up perhaps.

 

[jimmbo]

The 4 cylinder 50 was still a 50 in 1985, in the late 80s it became the classic 45. Nothing changed on the engine, except the Decal.

 

[racerone]

Appears to be a 1988 model.-----Change the water pump impeller as it may be running hot.

 

[QBhoy]

The 4 cylinder 50 was still a 50 in 1985, in the late 80s it became the classic 45. Nothing changed on the engine, except the Decal.

Was also the identical engine to the mariner 45 in the early days…but merc decals said 50.

 

[jimmbo]

In the early days of Mariner the 40 and 50hp were 2 cylinders.
Mariner and Mercury relabeled the 4 cylinder 50 to 45 the same year.
The 44 cu in block was introduced in 1958 as a 40hp, in 61 it was also used for the 50hp and in 62, a 45 and a 50

 

[QBhoy]

In the early days of Mariner the 40 and 50hp were 2 cylinders.
Mariner and Mercury relabeled the 4 cylinder 50 to 45 the same year.
The 44 cu in block was introduced in 1958 as a 40hp, in 61 it was also used for the 50hp and in 62, a 45 and a 50

They were indeed. Yamaha engines on the 40, 55 and 60. But the 45hp of the same era was a merc 4 cylinder the same as the classic 50, I’m sure. Like this one. These were around from the early to mid 80s…up to late 80’s, I’d think.

 

[jimmbo]

1985 it was still a 50, in 86 through 89, it became a 45 .