Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

redbrass_ca

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Dec 31, 2011
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Happy New Year to the members of the forum

I came upon this forum while working on 1976 Johnson Evinrude 20 HP.

This summer I acquired two old outboards full of parts. The most promissing was the 1976 20 HP evinrude. The outboard came in a variety of boxes as it was partly disassembled. The project was started back this summer and it has been long and tidious at times as the engine was stored for many years. After managing to remove the engine from the lower unit I noticed that the exhaust restrictor was partly melted ( see attached photo). I suspect there must have been an overheating problem. The engine block is the next part of the project. It is not seized.

I hoping to have the engine fully restored to fit on a transom of a 14 foot zodiac

I would like to know the importance of the role of the restrictor. What would be the outcome if it was not replaced (left out)?
Why is it made of plastic and not copper or aluminum?

Second question.

Some of the rubberized mount(vibration dampers) in some cases are cracking and delaminating. I believe most are now obsolete. How to make sure a mount is worth putting back on? How much flexibility should they have?

Third question.

Is "Never Seeze" a good choice when reassembling the outboard. The tare down process was very frustrating at times because various bolts sheared inside the casting threads which required drilling and re-tapping.

Can this 20 HP made easily into 25 HP?

Any advice would be appreciated

Terry
restrictor.jpg
 

Bob_VT

Moderator & Unofficial iBoats Historian
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May 19, 2001
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26,109
Re: Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

Welcome to iboats

As long as you use an aluminum based never seize (Do not use the copper based one) and make sure you are installing bolts into clean threads you should be fine.

Nope you are not going to make a 20 into a 25. A good running 20 is always better and more reliable then a "frankensteined" 25.

The restrictor creates proper back pressure and yes it is needed. It is an available part.

The rubber mounts are okay as long as they are in one piece.

Check your serial numbers ............ I am not sure Johnson or Evinrude made a 20 HP in 76 so you might already have a 25.
 

TN-25

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May 27, 2008
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623
Re: Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

Although the Johnson 20 / Evinrude 18 was discontinued after 1973, OMC did reinstate the 20 horse in Canada in 1975 for both Johnson & Evinrude. I believe the 20 was also offered all along in Europe. Just an FYI.

Although the 18/20/25 share the same 22.09 c.i.d., the 25 has a different exhaust bypass cover, different intake manifold & carb, plus a heavier crankshaft designed to be durable at the 1000 rpm higher that it needs to reach 25 horses.
 

Bob_VT

Moderator & Unofficial iBoats Historian
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26,109
Re: Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

Canada my bad :facepalm:
 

redbrass_ca

Recruit
Joined
Dec 31, 2011
Messages
4
Re: Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

Thank you very much for all your inputs. My Jonhson outboard is a model 20BA 76E serial C0043573. I believe the 76E indicates is was manufactured in 1976.

Terry
 

HighTrim

Supreme Mariner
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Jun 21, 2007
Messages
10,486
Re: Restoring a 1976 Johnson Evinrude 20 HP (New to Forum)

Yes that is a 76 Canadian build Johnson.
 
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