How to find the age of my motor with out the correct ID tag

[jrs_diesel]

I am rebuilding a what I think is a 70's vintage 6 HP long shaft Johnson. Here is my dilemma.

According to the ID tag on the transom bracket, it is a 6R77A, which tells me it's a 1977. A few problems with that though:

- The outboard is painted in Johnson green, except for the transom bracket which is white.
- The motor is of the LONGshaft variety, which tells me that the model number should read 6RL77A, not 6R77A.
-1977 is when Johnson switched to capacitive discharge (CD, called MagFlash I think). My engine has points ignition.
-1977 is when Johnson started painted their engines white, not green.

I do not know much of the prior history of the motor, other than it was attached to my sailboat (a Catalina 22). It has not been run in at least 10 years. It was run in salt/brackish waters, and not flushed out, as evidenced by some internal water passage corrosion.

Is there any other tags, stampings, or other ways to figure out what year this motor was made? Since I am rebuilding it, I want to make sure I buy the correct parts.

 

[1946Zephyr]

Re: How to find the age of my motor with out the correct ID tag

Well, posting a pic would be helpful and you'll find a quarter sized welch plug on the powerhead around the cylinder area.

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

Here is a picture of it. It's currently in the back of my truck, since I took it to work to press out a seized head bolt. I have it torn down right now but if any other pictures are needed, I'll take them.

In the picture you can see the white transom bracket, and a green engine. I have the lower unit out, but you can see the 5" leg extension.

This engine has seen better days, but I want to fix it up good.

I did find the welch plug and it has stamped upon it "J3563834"

 

[1946Zephyr]

Re: How to find the age of my motor with out the correct ID tag

Yea, oddly enough, Johnson only put the serial number on the welch plug, from what I've experienced. Evinrude will typically put model and serial number. Your motor definately looks like a 70's vintage. It actually looks like my 74 6hp but yours is a long shaft. Parts for those should be the same, all the way through the 70's with those. I was only able to find 6R77M and 6RL77M on shopevinrude.com. Not sure what the A stands for.

I think the best thing to do, is take your old head gasket with you and make sure all the holes line up with the new and of course, give the parts guy your serial number.

 

[tx1961whaler]

Re: How to find the age of my motor with out the correct ID tag

Somebody put new brackets on it because the saltwater froze the old ones up.
I have a 3hp that way, but I had the foresight to switch the ID plates when I switched the bracket. My memory is too shot to be remembering what goes to what after I Frankenstein one up.

 

[1946Zephyr]

Re: How to find the age of my motor with out the correct ID tag

Yea, I think it would be cool to make a "swatch 5.5" Take the lower unit off of a 1955 Johnson 5.5 and bolt it on 1957 Evinrude 5.5. Take the swivel bracket off of a 1957 Johnson 5.5 and put on a pair of transome clamps off of a 1959 Johnson 5.5 There you go my friends......a Frankenstein motor.

And what the heck, bolt on a powerhead off of a 1956 Johnson 5.5

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

Yea, oddly enough, Johnson only put the serial number on the welch plug, from what I've experienced. Evinrude will typically put model and serial number. Your motor definately looks like a 70's vintage. It actually looks like my 74 6hp but yours is a long shaft. Parts for those should be the same, all the way through the 70's with those. I was only able to find 6R77M and 6RL77M on shopevinrude.com. Not sure what the A stands for.

I think the best thing to do, is take your old head gasket with you and make sure all the holes line up with the new and of course, give the parts guy your serial number.

Best I could find out was the last digit (in this case the "A") was a revision, or series identifier during that model year.

So it looks like your 74? Do your cowling decals look like mine?

I think you are right about part compatibility. Only thing different is the leg extension, driveshaft, shift rod, and water tube.

Somebody put new brackets on it because the saltwater froze the old ones up.
I have a 3hp that way, but I had the foresight to switch the ID plates when I switched the bracket. My memory is too shot to be remembering what goes to what after I Frankenstein one up.

Thanks for that tip. Just wish whoever had this before me thought to switch the plates.

Even the white bracket had a minor issue when I got it. The clamping bolts were seized. Some PB Blaster took care of that though.

 

[F_R]

Re: How to find the age of my motor with out the correct ID tag

Based on the serial number, I say it is either a 1971 or 1972. This from my little stash of serial numbers. I know that #3,669,313 is a 1972

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

Thank you for posting that F R. My boat is a 72 Catalina 22, so this may be the motor that came with it.

Would an OMC/BRP shop be able to look up the serial number?

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

If this helps date the engine, it only has 3 controls on the front. The choke, slow speed adjust, and the pull start.

 

[1946Zephyr]

Re: How to find the age of my motor with out the correct ID tag

So it looks like your 74? Do your cowling decals look like mine?

I think you are right about part compatibility. Only thing different is the leg extension, driveshaft, shift rod, and water tube.

Yep, my 74 6hp looks just like that, so yours, is pretty close to the same year as mine, if you can't accurately get the right year. I don't think you'll have any issues getting parts, because they're all pretty much the same, throughout the 70's.

 

[F_R]

Re: How to find the age of my motor with out the correct ID tag

If this helps date the engine, it only has 3 controls on the front. The choke, slow speed adjust, and the pull start.

That information doesn't help much. That is a pretty universal description. As already said, the motors are pretty much the same for several years, so parts are pretty much the same also.

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

Great, thank you guys.

 

[jrs_diesel]

Re: How to find the age of my motor with out the correct ID tag

I found it! It's a 1972 model. I was on evinrude's website where they still have the parts diagrams. I was able to match the motor cover, and several key internal parts (gear shift linkage, rewind starter mounts, and a few others).

I'm a little excited now. Can't wait to get parts and get this puppy running again.