63' merc 850 lower unit compatibility

[LV2BT]

Hoping someone can help, I have a 1963 inline 6 merc with bottom end issues. It appears the previous owner tried to remove the bearing carrier and broke it in half. The 85hp power head still runs as far as I can tell. Since I can't find a 63' lower unit, I am considering newer parts but can't find any compatibility info earlier than 1965. I have 2 basic questions:
1 - Can the 63' lower unit be swapped with a newer one, say late 60's early 70's?
2 - Would the bearing carrier from any newer unit fit my 1963?

Any help would be appreciated.

As a side bar, it would be nice if someone could publish a merc lower unit/upper unit compatibility chart as it seems to be a popular questions.

 

[Jhoppy]

Re: 63' merc 850 lower unit compatibility

JR just answerd the lower unit compatibility Question for me on the in-line 6.

http://forums.iboats.com/showthread.php?t=367473

hoppy

 

[crem1]

Re: 63' merc 850 lower unit compatibility

Any chance of getting the info on a 73 MERC 500 lower unit? Is it a pin or a stainless drve shaft and how interchangeable is it with other years?
Thanks

 

[OldMercsRule]

Re: 63' merc 850 lower unit compatibility

Any chance of getting the info on a 73 MERC 500 lower unit? Is it a pin or a stainless drve shaft and how interchangeable is it with other years?
Thanks

There is a chance if ya start yer own thread. Better 'splain what ya mean by "pin". JR

 

[OldMercsRule]

Re: 63' merc 850 lower unit compatibility

Hoping someone can help, I have a 1963 inline 6 merc with bottom end issues. It appears the previous owner tried to remove the bearing carrier and broke it in half. The 85hp power head still runs as far as I can tell. Since I can't find a 63' lower unit, I am considering newer parts but can't find any compatibility info earlier than 1965. I have 2 basic questions:
1 - Can the 63' lower unit be swapped with a newer one, say late 60's early 70's?
2 - Would the bearing carrier from any newer unit fit my 1963?

Any help would be appreciated.

As a side bar, it would be nice if someone could publish a merc lower unit/upper unit compatibility chart as it seems to be a popular questions.

I dunno specifically 'bout the '63 850 inline6.

Chances are if it's Black it will fit.

The first Black Lady was the 1962 Merc 1000.

Hopefully: some of the big guns here will say fer sure.

Me "guess" is yes, butt: I don't bet big $ on a "guess". JR

 

[LV2BT]

Re: 63' merc 850 lower unit compatibility

Thanks JR,

I appreciate your guess. I thought I read somewhere that I might need to modify the shift linkage however. I'm not opposed to this idea but I would like to confirm what I am getting into before I go out and buy a different year. This fixer upper is only intended to get me through 1 or 2 seasons so I don't really want to sink big $$ into it. I'm hoping in a few seasons, I can scape up enough cash to get a remanuf. 90' 115hp w/tilt & trim.

 

[LV2BT]

Re: 63' merc 850 lower unit compatibility

oh... and yes... it is black but it seems there is some white paint showing through here and there behind trim pieces etc...

 

[emckelvy]

Re: 63' merc 850 lower unit compatibility

Here's some info which may help:

For any later-style lower unit being adapted to an older non-exhaust-tube motor, you'd have to shorten the shift shaft; plug up the side vents; and modify the brass reverse lockout cams & the plastic spacer spool from your motor to fit the later-style unit.

Some later-style units have different ways to seal the driveshaft/crankshaft area; early "new-style" units have an O-ring groove same as your 850. Later units use a crankshaft seal assy with non-grooved driveshaft. For these, you'd either need to cut your own O-ring groove or pull the powerhead to press in a seal assy at the bottom of the crank. I've done the O-ring groove with a grinder wheel and that method works fine. If you should ever have your powerhead off for R&R, the crankshaft end seal is a nice upgrade.

At any rate, you could use a much newer unit with benefits such as stainless driveshaft & improved gearcase design, and different gear ratio. The 2.3:1 ratio (found in 66 c.i. Fours; "800", "850", 80hp, 75hp) works very well with these older inlines and improves your range of prop size selection. Typing this it comes to mind that later model 650-4's had 2.3:1 gears as well.

Note that you can find plenty of 2:1 gearboxes in later-style as the majority of Inlines used that gear ratio. Don't use one from an early 1150 or 1350 as the 1.78:1 ratio wouldn't be a good choice for your motor.

BTW if you were to find a "650" lower unit of the same vintage as your 850, it's a bolt-on with no mods required.

Anyway, that's in in a nutshell!

Once you find a newer lower unit we can go into the modifications in more detail. I did this to my old '64 850 (converted into a 1000) and it worked great.

HTH.............ed

 

[LV2BT]

Re: 63' merc 850 lower unit compatibility

Ed, your post helps a great deal. Based on this, I'm no longer concerned about getting a newer unit. I will certainly be looking for the 2.3:1 gears. I don't expect a problem finding the newer units as I am near a decent size boating comunity.

Once I find a unit, I will certainly be posting back for details and will likely post the conversion process for others to benefit.

Thanks again,

CT.