Mercury Mark 58E Lower Unit Issues (Stuck Lower Shift Shaft & Impeller Cover

[tjook777]

When I removed the lower unit the lower shift shaft did not come with it. It is frozen/corroded to the upper connection. Any suggestions on the remedy for that when I put them back together? Is it an issue? Shifting was working prior to taking off the lower unit.

Separately, the impeller cap is frozen and I am having trouble getting it to free up. I haven't used penetrating oil yet or heat. Any suggestions?

Thanks!

 

[tommarvin]

If that was a force 125hp it would be over, but it looks like it has four ridges that slide into something.
Im not sure the shift shaft comes out of the mid section, i would bet alot of money it does, gently try to wiggle the shift shaft out of the mid section, it sould come out.,Alway grease everything well so nothing gets corroded and you cant get it apart.If the shift shaft comes out you have to put it back together the way it came out, focus.

The impeller cap, dont use heat, spray it every day with penetrating oil, we use Marvel Mystery oil it works best for us.
Gently tighten the bolt,then loosen the bolt,back and forth until the bolt comes out clean the threads and slather with lots of marine grease.
Wait just looked at the picture its a spanner wrench,spanner wrenchs are good to use if they work,50% of the time its corroded to much most of the time you have to get a big punch or small chisel to put it one of the four holes on a 45 degree angle tap with a hammer and spin the top off.

 

[GA_Boater]

Tom - You never worked on one of these, so any advice you give is misleading.

The water pump is a cartridge type, nothing like you or any Force has ever seen. It takes special tools and some knowledge to remove and replace.

Here is pitiful Youtube video that doesn't show removal and reassembly, but the parts are shown.

 

[Chinewalker]

The lower unit has to come apart to get the shift rod back in. The cam rides on a spring loaded pin, so when the shift rod com s out, the cam gets pushed out of alignment. Good idea to invest in the 1965 and prior Merc manual as it will pay for itself in saved frustration.

 

[DeepCMark58A]

I made a tool that works with an impact tool to get the water pump cover off, they are a bear to get off usually. If you own an old mercury the manual is a must have. I would also look in joining an old mercury website site that a guy named John ownes, many experts there.

 

[DeepCMark58A]

This is my water pump cover removal tool

 

[DeepCMark58A]

I would also recommend that since you are going to have the lower unit apart that you invest in new seals and bearings for the lower unit.

 

[tjook777]

I broke down and bought the tool to remove the impeller cover and it worked quite well. It was a bear to get the impeller off of the drive shaft but I was able to chisel that off as well. Just waiting on the new impeller. I did buy an online service manual which is helpful.

I would assume pretty much everything needs to be removed from the lower unit to get to the shifter rod connection to the lower unit? From the manual there are a good amount of special tools required. Have you guys run across any good video's pictures of a full lower unit rebuild on a similar older Mercury?

Thanks!

 

[DeepCMark58A]

John's Old Mercury dot com is the best resource it is a pay to get on website but trust me well worth the $15.