1970 40hp Johnson lower end swap

[Hercplt]

I have two motors, a '70 Johnson, and a '67 Evinrude. Both 40 hp. Effectivly the same motor. The 67 motor has a good lower end and I was planning on swapping them. Is this a relativly easy job?
Rich

 

[Daviet]

Re: 1970 40hp Johnson lower end swap

Disconnect shift linkage and attaching bolts and swap lower units. If you are not sure of water pump condition, this would be a good time to replace it.

 

[Hercplt]

Re: 1970 40hp Johnson lower end swap

so exactly how do I disconnect the Shift Linkage? I had a look and can't figure it out. I guess I need a manual... but in the mean time... how the heck do I do it?
Thanks.
Rich

 

[Daviet]

Re: 1970 40hp Johnson lower end swap

Look on the starboard side of the exhaust cover for a plate held on by 2 screws, aprox 1" by 2", remove this cover. Underneith that cover is another cover held on by 2 screws, remove that cover. Take a flashligt and look inside and you will see a brass connector for the shift linkage, I think the bolts have a 3/8 or 7/16 head, can't remember for sure. Move the shift linkage so that you can access the upper bolt and remove it. If you have all the bolts out the lower unit should come down. Notice that the shift linkage rod has a detent or grove in it. When you reassemble the lower unit the bolt that you removed MUST go through this grove. When you have the lower unit down, take a screwdriver and spread the clamp just a little and it will slide back on easier. Don't spread it to far or the bolt will not screw in properly. The connector is brass, don't strip the threads when you tighten the bolt.

 

[Hercplt]

Re: 1970 40hp Johnson lower end swap

Ok... I got that all done. Thanks for the advice. It worked out well.
Now I have it all apart and the rear of the motor removed too..(the cover in the back). There is a large ring seal that the front and back covers fit into and it wraps around the exhaust, drive shaft etc... How do I replace it? I ripped the old one off as it was rotten, but how does the new one go on?
Wow I need a manual...

 

[Daviet]

Re: 1970 40hp Johnson lower end swap

I know what you are talking about, but I can't recall replacing one. I will look at the manual tomarrow and post an ansewer.

 

[F_R]

Re: 1970 40hp Johnson lower end swap

No insult intended, but if you had trouble figuring out how to disconnect the shift rod, you are in for quite an experience replacing that seal. The powerhead has to come off. Then the exhaust housing (the part that the seal goes around) has to come out of the front half of the shell.

This is an oversimplification, there are many parts that have to be disconnected or removed to accomplish this.

Good luck.

 

[Daviet]

Re: 1970 40hp Johnson lower end swap

I looked it up in the service manual but it did not say what you have to do to replace it. By the looks of it in the manual, F R is correct, as he always is, there is some disassembley required.