TOPIC: 1976 Merc 850

One of the guys on CGOA is parting out a parts boat, got a chance on a 1976 Merc 850 with PT&T. Has one cyl low on compression, but the Trim setup is worth the asking price. (Assuming it will work on the Stack 6 motors). Any thoughts on the 85 HP (3cyl?) motors? I was thinking if my Merc 1000 doesn't pan out, might be a good candidate for rebuild and power on my GT-150, but funds really low right now. Could probably make the deal happen, but wanted to get some input from "the gang" here first.

The 1976 850 shares the same mid as the 1500. Lower unit will work too but it may be 2.3-1 instead of 2-1 gears. Power trim is the same.

If you were to stumble onto a 1500 a newer 1150 just powerhead you could make it work on that mid. But it sometimes is just easier to find a complete motor.

If you get it cheap you can either rebuild the 850 or just use it for parts. That motor is a 4 cyl by the way.

Conrad

Thanks Conrad, just kicking around the idea, sounded good to me. (Motors are easier to "hide" in the garage!)

milkdud wrote:

The 1976 850 shares the same mid as the 1500. Lower unit will work too but it may be 2.3-1 instead of 2-1 gears. Power trim is the same.

If you were to stumble onto a 1500 a newer 1150 just powerhead you could make it work on that mid. But it sometimes is just easier to find a complete motor.

If you get it cheap you can either rebuild the 850 or just use it for parts. That motor is a 4 cyl by the way.

Conrad

So let me understand this...you can put a 115 Tower head on the 850 midsection? or a 1500 ...interesting... what specific years can you make this interchange?

so the Towers where platformed from the bigger 4 cycl motors... nice... is there a book or manual out there that has this kind of info in it? what you swap to one motor to another? .....like taking carbs from a bigger motor to fit a smaller one for a lil more juice?

Just learn from others like I did I guess. Online parts diagrams help too.

The 1973 850 and newer is the same as the 1973 and newer 1500's and 1150's. Even the late 1400 is the same. and the late 90.

Kinda like the old 650 4 fits the same mids as the 1000, old 1150, 1100 900 950 1250 1350.

Usually merc used the same mid and lower of the 4's and 6's during the same time periods. Saved money for them.

The big years to remember are 1965 and 1973 Both of these years they started new designs and the years pervious to these dont interchange.
Conrad

On the powerhead swapping, be aware that the 850 has a smaller adapter at the bottom of the tuner plate and if you don't change this out when bolting an I-6 to and 850 mid, it'll strangle engine performance. This caveat applies only on the '72-up mids which have a 'split' tuner plate design with the (2) rectangular-ish exhaust tuning ports in the plate.

Earlier models with the same bolt patterns ('65-'66 thru '71) have a more "open" exhaust adapter design and will pretty much interchange. The 99-c.i. Sixes have (2) extra 5/16" mounting thru-studs at the very back of the powerhead. This requires use of the matching exhaust adapter plate, but since the holes are only in that plate you could still bolt right up to an earlier I-6 or I-4 mid.

That's just a broad guide, there may be some other subtle diff's I can't recall that the Good Dr. FrankenMerc might!

Cheers & happy swapping........ed

I couldn't stand to pass on the deal, supposed to get it next weekend!

Good example of not being in the same city, handing the man cash to "seal the deal". Sent email to confirm the transaction, got reply he sold it to someone else. Oh well