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1959 Mercury Mark 35a - Gear cover is off - now what?

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Boatsnhoes

Contributing Member
Well I got the gear cover off without much drama once I got the specialty tool delivered, but I find myself in a similar position as I was once I got the water pump cover off - now what?

I was expecting the now-exposed part shown in the pictures below to be more readily removable, but I can't see anywhere to get any purchase. So now how do I get any farther into the lower unit?

I'm referring to part 55 here: https://www.crowleymarine.com/mercury-outboard/parts/1109_16.cfm - the bearing carrier assembly. How the heck do I take that out?

To recap - I have all the covers off - shift shaft, water pump, and gear cover, but in each case it seems there's another layer that I have no idea how to get through. Hope someone can help out!

[my phone isn't emailing the pictures so I can't get them on my computer to post here - once they come through I'll edit the post to include pics]
 
Clamp the propshaft in a hefty vice.-----Now bump the housing to remove propshaft and bearing carrier.----There are other methods if the assembly is stubborn.
 
Done! Popped it right off, thanks everyone. everything looks surprisingly great inside, all very well oiled and shiny , which leaves me with two problems that I can’t explain:

1) why was I stuck in reverse? It may be just because it is extremely difficult to shift, and I was going too easy on it, but it feels more than that, it feels like something is binding. The shifter cam looks good and smooth as does the pointed cylinder it makes contact with. Is it possible the spring is too strong or something?

2) why can I hear every tooth engaging? When I turn the driveshaft I can hear(and now also see) each tooth of the pinion gear engaging the reverse gear. This was happening when it was all buttoned up, too, to be clear. I can get a slight improvement by physically pulling up on the driveshaft as I turn it. What could cause this? Perhaps a missing shim or something?

3) what was the grinding noise? It still happens occasionally but I can think of no reason there.
 
??----The spring has been in there for 60 years.----I doubt that it is " too strong " today !----All outboard lower units are smoother when you pull up on the driveshaft !
 
My guess is that the spring was replaced with something that was too strong. I'm comparing the ease with which this guy: https://youtu.be/ZQo8Gi2ZaGI?t=234 moves the dog spring (using just a thumb) compared to mine. I need to put full body weight on that spring to get it to compress all the way (to the point it would engage the forward gear).

I'm going to take apart the dog and replace that spring with something weaker unless anyone says otherwise. Are these motors notorious for strong dog springs or something? I'm not exaggerating at all when I say I have to lean full body weight into this thing to move it.

The only other thing I would say is that the total travel of the dog seems slightly less than it should/could be - even at full travel the dogs are not completely mated with the teeth in the forward gear. They would drive it in forward (if I could get it there), but it's not a perfect mating surface.

Thanks guys.
 
???----When you compress the spring you are moving the clutch dog to engage REVERSE !-----I think replacing the spring will be a mistake !
 
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My mistake, but the point still stands - the gear is way harder to move into reverse* than it should be (at least based on what I've seen around on youtube).

I took it apart to get a look at the spring. Nothing to note about it really, seems like the right spring at least in terms of size, it's just super stiff.

Could being left fully extended over a long period of time have made it favor that position more strongly?
 
That youtube video is about a newer LU and they've changed the pressures and cam, the shift setup on your motor (and my 850) uses a stiff spring to push the clutch dog into the F gear and it takes some force. Turning the shift shaft takes more effort that your fingers when I reattach my LU in the spring I use vise grips to turn the cam into N.The way to test the play in the gears is to pull up on the driveshaft and push in on the propshaft then slowly rotate the propshaft back and forth to feel the play.
 
Have you taken the whole shifting unit apart? The spring can only be accessed by removing the guide block and pin in the clutch dog; if it fell out then the unit has been assembled incorrectly
Lower-Units0052.jpg
 
Alright, well I'll take everyone's advice and just reinstall the original I guess. Thanks for the advice guys.

To be clear - I did disassemble the assembly shown in the picture you posted, Quicksilver. Nothing fell out or anything like that (until i took it out)

Anyone have any advice on reassembling the whole LU? Any lubes or anything i should be using? Anti-seize?
 
Use anti-seize on both of those big aluminum nuts, and oil on the seals and where they touch.

I vacuum test the assembly after it's all together, to see if it will maintain a vacuum.

Jeff
 
You can pre-lube the bearings and the one at the end of the propshaft (inside housing) with marine gear lube - you should test the F gear/driveshaft play. To test gear lash pull up on driveshaft, reach in and rotate the F gear back and forth to feel the play, it should be very slight and not binding but not very loose, look at the wear pattern on the F gear - it should be across the whole face.
Don't speed test the unit unless it has lube in it - there's a bearing below the waterpump.
 
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Got it. Any recommendations on the type of oil to run in the LU? I saw it was originally supposed to run grease, but since that's scarce oil would work, I just don't know what kind.
 
Your local----John Deere -----Farm supply will have something called ----Corn head grease-----A thin grease that will work fine in your old Mercury.-----Will not leak out like oil could if shafts / seals are not in the best shape.
 
...or you could just replace all the seals and make the unit leak tight. I do that with mine and run gear oil (which makes more rpm).

Jeff
 
I'm already replacing all the seals (they're on their way) and I like the sound of gear oil - that lubriplate is expensive. What gear oil do you use?

My current plan is to get one bottle of lubriplate and use it as an assembly grease. Then I'll fill the whole thing with gear oil.

What gear oil do you recommend?
 
I don't know if the grease will be compatible with gear oil, maybe just use gear oil completely. I use Amsoil Gear Lube it's synthetic and my LU is watertight so I leave it in for a couple of seasons. If water does get in it has 10% water contamination protection.
 
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