Mark 55 magneto drive

[jeff-register]

Mine was stuck, no advance possable. Heated it & it moved until it cooled off then stuck again. Pumped full of new grease & now after sitting all night by the heat it still is very hard to turn & is not acceptable. It must be free to turn as I’m using a tiller. Yes I know Mk 55 didn’t come with a tiller but my mk 55 powerhead has mods. Has anyone ever bent all the tabs enough to separate the two pieces & have enough tabs left to hold the assembly together. I believe mine is full of very hard dried grease as when heated I get black tar not grease from it. I too believe this is the first time it has ever been serviced. Much more in the mag needed very much work to be corrected. Help & thanks,
Jeff

[beerman57]

T

[jeff-register]

Beerman,
Yes you are correct. The first bearing is directly below the sheave in the top of the mag drive. In the bottom of the drive no bearing is needed as the shafts have male & female splines. The magneto/ distributer is bolted to the bottom of the drive assembly. the second shaft has four magnets as each two run two cylinders as it fires every 90 degrees. Below the magneto is the distributer & rotor. The coil is beside the distributer all in one housing.
I have ordered the three bearings needed but the shaft bearings don’t have anything to do with the timing advance. it is like two pipes, the inside one sliding on the outside. Right there is my problem where they slide. It is full of ages old hard dried out grease & no way to get at it to clean it. It is held inside the housing by bent tabs, two each & 90 degrees apart. If I bend the tabs I might break them off. Also four tabs hold the very top bearing is located by the tabs only reversed to the inside to hold the bearing in. The drive assembly is not made to come apart on early mags & was ordered as an assembly. I’m going it soak it in gasoline first & if that doesn’t free it up I’ll try air conditioning coil cleaner made for aluminum evaporator coils as they get dusty & muddy from moisture. Has anyone ever taken this 58 mag apart with bending the tabs. I think it needs to be scraped to get it clean again & use 105 to grease it. Please anyone?
Jeff

[RICHARD A. WHITE]

I would think you could probably bend those tabs open it up and do it again, like a few times before they might break. The metal will be malleable(sp), and should easily allow you in there once. Give it a whirl, worst that can happen is you might need another housing, but I doubt it. Trust your instincts bud, and give yourself some credit. fix that sucker proper like…LOL

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[jeff-register]

Richard,
I’m going to let it soak in a coffee can full of gasoline for a few days. After pumping in the regular ball joint grease I do know it needs a much lighter grease like 105. It needs to be totally free as it’s part of the throttle linkage. The bottom connects to the tiller linkage & the top actuates the carbs.
I just want to hear from someone who has bent the tabs & returned them to position. I know to get it clean it must come apart.

[r-c]

There are two kinds of towers. The early ones had brass tabs, the later stainless steel. Which I think you have. In either case, bending the tabs usually break one or more, with the brass ones almost impossible not to break all. If you lose one or two it may still be enough to hold it together.
Your one fix is not to soak in gasoline but I would suggest carb cleaner. The kind you can buy in one gallon or a five gallon bucket as it penetrates better.
I like the ideal of heating it is probably better, but once hot pump in the new grease to extract the old until both ends show the new grease. 105 can work but I like something a little thicker so it won’t want to leak out so easily. More in the vain of wheel bearing grease.
Now for a racing trick. Disassemble and don’t worry about breaking tabs. Cut down the top of the outter sleeve a 1/4" or so in a lathe. Mark the inner sleeve for a groove and use a snap ring. I tried to look for the snap ring size and this info is lost in all my racing notes. However it is a standard snap ring.
The top bearing there is often good and I would leave it alone if it turns freely. There are only four tabs to hold it in and if they break there is little hold the new one. You could cut the depth deeper and try a snap ring above the bearing. But you also have to cut the step in the drive shaft an equal amount.
Bottom line it maybe easier to find a replacement. However I think the heat and pumping in new grease is the easiest fix to try first.

[wiscoboater]

Just wondering if a tab did break off on you, could you use a stout zip tie at that location on reassembly? Or is this a motor you want correctly restored?

[Pondrocket]

Jeff,

Something like this?

Travis

viewtopic.php?f=5&t=3590&p=19446#p18701

Travis
www.waterhogsworks.com

[Anonymous]

the last pic is the one those tabs are part of the inner housing and are made of a brass like material and breakoff easily. when you bend them back in place is when they break off.

[jeff-register]

That is my 4-D magneto. The upper bearing was very rough but got it out waiting on the same. I’m going to use a brass drift to install the 3 bearings. It should function well afterwords,
Thank you everyone!
Jeff

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