74 Browning Montego with mercury, engine idea swap

[swishercool]

I just bought this boat for 150 needs a new motor, what mercury engine can I swap into this that will bolt up to whats on there right now? thanks for the help

 

[Scott Danforth]

Depends..... What's in there now

 

[swishercool]

a mercury 50 hp

 

[Scott Danforth]

you do realize over the last 80 years, there have been about 12 majorly different mercury 50hp motor designs if you have an early Merc, the bolt pattern on the clamp is different than the later ones. the bolt pattern is now a standard.

however you can bolt anything you want on the back if you have to redrill holes, seal up the old ones and redrill.

going to guess since the boat is a 1974, that the motor is about a 1974. the BIA bolt pattern that was standardized in the mid 80's was modeled after the Johny-Rudes. so if you want to make it easy for you bolt wise and control wise, replace your mid 70's Merc with a mid 70's to early 80's merc

 

[swishercool]

So i have a mercury 850 with thunderbolt ignition

 

[Scott Danforth]

The 850 is an 85hp, not the 50hp that you mentioned in post #3

 

[swishercool]

yea, I was wrong, would I be able to put a newer mercury engine on and should I stay this this kind?

 

[jimmbo]

Well the mercury 850 was offered as 4 cylinder from 1973 - 1977, there was a 6 cylinder 850 in the early to mid 1960s. 1984 was the year Mercury switched bolt patterns on the 66.6cu in 4 cylinder and the inline 6s.
As mentioned earlier, you can bolt whatever you want. It would be a little easier to use an older engine, thus sparing you filling the old holes and drilling new ones. But a newer engine, most of the time will have power trim built in

 

[swishercool]

thank you for the help

 

[swishercool]

Would a 650 mercury be able to switch with the 850?

 

[jimmbo]

If it is a 4 cylinder 65hp, no problem. A 3 cylinder, I think the transom bracket is the same, so maybe.

 

[swishercool]

thank you so much