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Mercury Mark 58A

R

regrubuen

New member
Hi all,

I'm 16 and fairly experienced at preforming basic repairs on boat motors (ie. changing gaskets, and cleaning carburetors on a 1973 2hp Evinrude). I just bought a 1959 Mark 58A Super Thunderbolt 45 hp for $60. I want to see if I can get it running to the point that I can stick it onto a 1959 Glasspar Trident that is my Dad's. Any help and or recommendations would be greatly appreciated. Currently all that I know is that the water pump is broken. I need to take it apart and clean everything as you can see in the pictures. I was wondering if there is anything to watch out for, such as the timing belt, or magneto. I am pretty good with understanding the mechanics of boats having grown up around a 1993 Johnson 90hp VRO, a 1973 Evinrude 65 hp, and a 1973 Evinrude 2 hp.All help is welcome!!! Thanks!​
 

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Only 16? Good for you. I started on Mercs while about that age (although 50 years ago).

That copper water tube needs to go back up there inside the housing, which can be done with a tiny flashlight and lots of patience. Tap it in place when you line her up.

The timing belts last a long time, but if it's dry rotted you'd better replace it. (Buy it from this site, please.)

The carbs will need cleaning, and the fuel pump diaphragm replaced.

The LU parts look okay, but find that missing vane or it could plug up the power head.

Let me know when you are ready to put her back together.

Jeff
 
Thanks fastjeff, i really appreciate your help. Do you (or anyone else for that matter) know anything about the 58A's? and also what do you mean by the missing vane? Also where and how do you recommend starting restoring this motor? I want to do it the right way, adn get it looking like it just came off the factory line! Thanks!!
 
Thanks... I think i'm going to restore everything besides the lower unit, just because it supposedly makes the motor run faster, and also buying a new lower unit will cost a lot, and will be hard to find
 
The missing vane is from the impeller in the photo. Your motor has the thru-hub exhaust of the later early Mercs. There's a few of them out there still.

Jeff
 
Are you looking for a pretty motor or a good runner ?---------I would tear the engine block down for full inspection.-----Will likely need new rings / seals / bearings.
 
First, do a compression test and see if you have to. If it has 110 to 120 psi, leave her be. You need to replace the crank seals. This is done by pulling the bearing caps off; the top seal comes out easily, but the lower requires removing the bearing first. (Let me know when you want to tackle it, and I'll walk you through the procedure).

Jeff
 
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