RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Nebkroz

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Jun 19, 2011
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I need help knowing how to drop the lower unit completely out of the upper unit. The lower unit is bad (cracked) and I have a replacement lower unit from an RDSL-23.

I'll need a step by step since it doesn't seem very obvious to me, especially how to release the shift pin.

Thanks
 

lindy46

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Shift rod coupler is under the little oval plate on the side of the leg. COMPLETELY remove the lower bolt from the coupler to free up the lower shift rod. You also have to remove the rear exhaust housing, held on by about a dozen or so Phillips head bolts, to get to the large bolt at the back of the motor which goes in from the top. Then remove the smaller bolts which hold the lower unit on - they go in from the bottom. The lower will then drop down.
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Could you help me out? The shifting mechanism isn't working after I swapped out the lower unit. The "forward" position is neutral, the "middle" position is reverse, and...there is no forward. The shifting mechanism is really shaky and loose. Any advice?
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Actually, I think it might have to do with how I changed the lower unit oil. I completely pulled out the screw on the side that has a philips head. It is actually a pin, too. Then I discovered the flat head screw on the back and drained it through there. When I put the philips screw back in, it wouldn't go. Something was blocking it. I stuck in a paper clip and moved some stuff around (lifted something up) and then it went in. Did that pin/screw (the philips head) somehow attach to the shifting mechanism? Is this why I can't shift?
 

wilde1j

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

You need to get the hole in the shift cradle lined up with the screw hole, then replace the pivot screw. An awl makes a good tool to use, you will need a flash light, and since gravity is your enemy here, lay the motor on it's side. I hope you are very patient. This may take a few hours. I would try to find an online parts list, so you will have a clue as to what's inside.

Next time, get an OEM manual and read it.
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Thanks Jim....lesson learned.
 

royal0014

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

marineengine.com will have the parts diagram for that engine. 'Ya can zoom in to get a better idea of what goes where.

The manuel would have told you don't pull the phillips screw ;)



<<)))(((>>
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Yeah. You can't imagine how angry I am with myself right now...after all the hard work I did right...

When I line up the hole and put the pin/philips screw in, it locks the shifting pin. Something is not lining up...I can't move the gear shift mechanism once I have the pin in..

I'll checkout the website.

Thanks.
Any more advice would help.
 

wilde1j

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

The shift cradle has a hole in it. That's what the pin must go through for it to work.
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

I have maneuvered the cradle around and lined up the hole with the philips/pin hole and put in the screw. Once I do this, the shifting mechanism locks. It can't move. What else could have slipped out of place down there to make that happen? Am I going to have to pull apart the area behind the prop and see what is going on?

I should mention that I ran it on the water before I knew it was not shifting. I knew there was a problem because it would only go in reverse. Did I screw up (bend or rip apart) the internal mechanisms by running the motor when things were not lined up down there?
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Any advice? It would be much appreciated.
 

Tim Frank

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

At this point, if reinstalling the pivot pin properly does not allow the L/U to shift properly, you will have to break into the L/U and see what is going on.
Whether you want to try this before you have a manual for reference is your call.

We'll help if we can....;)


BTW, are you 100% certain that those L/U are interchangeable?
There have been many odd symptoms generated (and discussed in here) with non-compatible lowers being swapped.
Just 'cause it looks like it should work, doesn't mean....:eek:
 
Last edited:

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Thanks for getting back with me, Tim. I actually removed the L/U to maneuver it around easier. Once I have put the pivot pin in, I can't move the shifting rod by hand. It is completely locked. Because of this, I haven't tried to replace it and try moving it with the shifting lever. I just assumed that if I couldn't do it by hand, it probably wouldn't work with the shift level...

I'm planning on cracking into the L/U and see what is going on.
 

lindy46

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

If the pivot pin is properly installed and the shift yoke hasn't slipped off the shift cradle, the shift rod should easily move up and down by hand.
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

Hey Lindy46 - I've done some searching. Because the pin is properly installed, and the shift rod locks down, I'm assuming the yoke has somehow slipped off the cradle. I'm going to have to dig into the L/U and get things lined back up.... Hopefully it won't take too much time. We'll see.

Thanks for the info. I'll let you know what I find out.
 

Nebkroz

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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

So..thanks to all for the help. I took off the skeg and discovered that the yoke had in fact slipped off the shift cradle. Got it back together, and it is shifting just fine now.

However....another problem has developed related to the ignition.

It was running rough at idle (surging, popping, etc.) and now it won't start at all...

I grabbed my air gap spark tester and both wire have nothing...

Any ideas on where to start?

Distributor, points, coil?

Any help would be appreciated. Why would it work some times (rough) then not at all....?
 

Cofe

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Apr 23, 2009
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Re: RDSL-25D Johnson Seahorse 40 HP Lower Unit Removal

It would be best if you started a new thread with your new problems. More people that can help with that problem will see it.
 
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