Giving new life to a 1981 50hp Evinrude

[ravihv89]

So I picked up this motor about a week ago in a trade. She wasn't much to look at and I was told she ran last time they tried. Unfortunately that was about 2 years ago. So I built a stand and went to work looking at what I'd gotten myself into.

Here she is:

Honestly I think it looks pretty good, but then again the only other outboard I've owned was a 91 200hp Johnson Oceanrunner which looked like someone beat the tar out of ruthlessly. When I saw the wiring, I became a bit upset.

I really hate butt splices. And I don't even know about the duck tape...

Luckily the wiring from the power pack to the stator and to the coils were left unmolested and were in excellent shape. So first order of business is to properly redo the rest of the wiring. Here are my questions:

Also in this previous picture, is that thing at the 10 o'clock position from the upper spark plug with the brown w/silver wiring the temperature sensor? My gut tells me yes and the manual seems to confirm this but I'm not sure.

And these are just observations I made:

I just realized my pictures are cut off, so let me state where the arrows point. The top arrow points to a linkage off the throttle that seems to catch one of the two sets of wires to the stator when you open the throttle. The second points to a random piece of wire tied off to one of the carb controls. The third is me just wondering if that small device on the side is the electric choke, which I believe it is, but the way it is currently wired it would not seem so.

If I made a mistake anywhere, feel free to correct me.

Thanks for the help!

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

I got thru all the wiring and the new wiring harness is in full working order. I found the starter was shot (rebuilt with new brushes-works well now), but the solenoid is bad. I also found that the previous owner/last person to work on the motor broke off 3 of the head cover bolts. Instead of fixing them, he just jb weld/superglued the heads back on.

While I wait for the solenoid and water & fuel pump parts I was hoping to repair these broken bolts and check the cylinders while I'm at it. My question is can I remove the cylinder head from the powerhead with the head cover attached? As the motor sits, the lower cowling is in the way of two of the broken bolts. I did loosen all the cylinder head bolts successfully but didn't remove them or the cylinder head just incase.

I guess my question is dumb, but I didn't want to cause more problems than I already have. I thought about removing the entire powerhead, but after removing the skirt below the lower cowling, I found 4 of the 8 powerhead bolts are rounded and the nut on the stud in center on the back is rusted beyond reason (not surprisingly in the same area as the three snapped head cover bolts).

Thanks for any help! Also Merry Christmas everyone!

 

[jasper60103]

Re: Giving new life to a 1981 50hp Evinrude

... My question is can I remove the cylinder head from the powerhead with the head cover attached? As the motor sits, the lower cowling is in the way of two of the broken bolts. I did loosen all the cylinder head bolts successfully but didn't remove them or the cylinder head just incase.

I guess my question is dumb, but I didn't want to cause more problems than I already have. I thought about removing the entire powerhead, but after removing the skirt below the lower cowling, I found 4 of the 8 powerhead bolts are rounded and the nut on the stud in center on the back is rusted beyond reason (not surprisingly in the same area as the three snapped head cover bolts).

Thanks for any help! Also Merry Christmas everyone!

Yes, you can remove the cylinder head with head cover attached.
Is this a salt water motor?
It seems like the previous mechanic tried to cover his foot steps by gluing the bolt heads back on. :facepalm:
Hopefully you can repair it. Also, this would be a good time to change the thermostat as well.

Sounds like you made some good progress. Good luck.

jasper

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Is this a salt water motor?
jasper

That's what I'm beginning to think although it's odd. You can't really tell but all the rust and rusted bolts are only on the back 1/3 around the spark plugs. Everything up front comes apart easily with no rust. I'm thinking it's been sitting outside trimmed up and the acid rain did that. The cover is cracked with a few holes. But that won't be done until the motor is good to go.

Thanks for the answer! I'm going to check the thermostat as well.

Also I redid the wiring harness with red and black tinned 14 ga I had on hand because I didn't want to buy several rolls of wiring just for a few feet. I am going to label them to make it easier with a dynamo labeler with waterproof tape in it. My question is this. If you were going to label them, would you put the function of the wire (i.e. "Electric Choke" or "Fused +12V") or the color of the original wire on the label? I think both would be overkill, but can't decided which would be better for me latter on or someone else.

 

[jasper60103]

Re: Giving new life to a 1981 50hp Evinrude

...

If you were going to label them, would you put the function of the wire (i.e. "Electric Choke" or "Fused +12V") or the color of the original wire on the label? I think both would be overkill, but can't decided which would be better for me latter on or someone else.

Yea, labels would be nice. Function would be my preference since a manual is required to decipher colors. Or you could go with both, e.g. Electric Choke (Brn).

jasper

 

[boobie]

Re: Giving new life to a 1981 50hp Evinrude

Put both function and color code on the wires. You won't be sorry.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Multi-post: Too many images

So I pulled the cylinder head today and I found good news and lots of bad news :uncomfortableness:. First off, here are the three bolts that were snapped off in the head:

They just happened to be all three of the ones over the cylinders. Great even less room for error.

More bad news when I started looking at the internals.

head gasket was intact but honestly looked like the original 1981 gasket.

The powerhead (yes I know, that's some mean looking build up in the water passageway under cylinder 2; it gets better)

Cylinder #1 looked good, slight carbon buildup around exhaust port.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Well, cylinder #2 didn't look as good

(not sure why I called it the head, I meant piston)

The fully blocked passageway goes to the cylinder head :facepalm:

water passageways in the cylinder head

Entirely useless and hopelessly broken temperature warning switch

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Check out that awesome cylinder head #2 damage

For those of you with good eyes, you may have noticed in the first post there is a picture of the cylinder head cover/head and what appears to be a piece of angle iron attached to the corner holding the ignition coil for cylinder #1 in place. You might also be scratching your heads. Someone how this didn't dawn on me till now, but obviously the motor was not manufactured that way. If you look, the upper corner mount for the ignition coil is broken off the cylinder head cover. Someone decided this was a good way to fix it. :facepalm:

So that's what I found today. I'm still scratching my head as to what might have caused the damage in cylinder 2. Any ideas guys?
I thought maybe it had something to do with the blocked water passage to the head, but that's just a guess. I know the temperature alarm was broken (the wire fell out when I first lifted the upper cover off the engine), so does the head/pistons/powerhead look like one that overheated?

Here's another piece of information. I did a compression test before ripping into it...well sort of I guess. If you've read above, you'll recall the starter solenoid is broken, so I had an assistant jumper cable the battery to the rebuilt starter while I read the gauge. Both were within 6 psi of each other (I think 95 and 101-I wrote it down somewhere but can't find it at the moment), so I know the compression was good.

The blocked passage leads me to believe that the water pump is probably not looking too good. Might get to pulling the lower unit tomorrow, we'll see.

On a positive note, I did manage to drill/re-tap those three broken bolts! Well I got two out without damaging the threads (just chased them with the tap) and then absolutely butchered the original threads on the third one with the tap :facepalm:. I'm going to have to tap that to the next size up and just mark/paint the bolt to identify that it's larger than the 12 other something cover bolts.

I'm going to make some labels with both per your suggestions and see how long they are. My main concern is them getting too close to hot components causing them to melt. After spending over an hour cleaning up the melted ducktape the previous "mechanic" used on all the wiring, the last thing I want to do is clean up melted tape.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Also I noticed that there was a empty area in the water jacket in the cylinder head cover that corresponded to a (factory) plugged waterway in the cylinder head. I'm suspecting this is for an optional water temperature gauge if the need arised. Here are the pics. Let me know what you think.

 

[bonz_d]

Re: Giving new life to a 1981 50hp Evinrude

Well at least it looks like you are enjoying this. Haven't seen anyhting too horrendous yet.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Well at least it looks like you are enjoying this. Haven't seen anyhting too horrendous yet.

Well that's reassuring. Here's a picture of the labels. I didn't get around to doing much else on the motor today. I went to the library (yes they still exist) to dig through microfilm looking for info on that mysterious fiberking hull this motor came with. Supposedly the HIN is no where to be found (the one I found on the transom doesn't start with the correct mfr. id, in this case FBK).

I went with the suggestion of both on the labels. Turned out good. Just hope they don't melt ray:

 

[Home Cookin']

Re: Giving new life to a 1981 50hp Evinrude

this is why smart mechanics don't work on old motors!

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Any good tips on clearing that blockage? I picked at it today and it's solid as a rock!

this is why smart mechanics don't work on old motors!

It's not that old...31 is the new ummm....16?

I got some more photos, which is good news for people that like bad news.

My trusty thermostat:

I know the general working of a thermostat (simply devices from what I understand) but even boiling/hammering this one, I couldn't get it to move a mm. Of course I went brute force on it because obviously it wasn't in a useable condition (I mean c'mon the o-ring was melted to it...).

I'm sure this thing might run one day :facepalm:

 

[jasper60103]

Re: Giving new life to a 1981 50hp Evinrude

Sounds like you're moving forward to fix?

 

[classiccat]

Re: Giving new life to a 1981 50hp Evinrude

Excellent documentation/pictures! It looks like you're making progress!

Did the person on the other-end of that trade keep a straight face??

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

Did the person on the other-end of that trade keep a straight face??

Well he did but I didn't expect much for a boat and outboard that cost less than the gas I spent driving 15 minutes to get there

Sounds like you're moving forward to fix?

I'm not sure at this point. That's why I was hoping someone could clue me into what exactly this damage/stuff means. I've bought about half the parts and fluids I think I need to get it running, but I'm thinking of just returning most of the parts (unopened) and turning the outboard's powerhead into a nice endtable :facepalm:

So any clue as to if I'm looking at an overheated engine? I lost my precision straightedge but the head is straight and the crank/pistions move freely. I haven't drained nor taken off the lower unit mainly because I don't want to waste my time if the powerhead is toast. I does shift freely and rotate the crank in both gears.

I might drain it just to see if there is any milk in it.

Any info is truly appreciated! I really don't think I'm looking at a bad powerhead, but then again I'm no expert

P.S. If I do scrap it, I do have a nice internal wiring harness to sell!!!

 

[jasper60103]

Re: Giving new life to a 1981 50hp Evinrude

I'm no expert, but I can't say its ready for the scrap yard yet.

Hopefully others will chime in.

 

[bonz_d]

Re: Giving new life to a 1981 50hp Evinrude

At this point what I think you need to do is get a head gasket on it and do a compression check. Before all else.

I just recently picked up a 1975 50hp Johnson that was in unkown condition. Came off a scrapped boat. 1st thing I did before buying it was to do a compression test and then a spark test. Compression was 150lbs on both cylinders but no spark. After further inspection and the compression readings I'd gotten I paid the man the $100.00 and loaded it into my truck. After spending a little time on the electrical and finally getting good spark I put some fuel to it and it started right up. Did I get lucky? Maybe!

Again, from what I've seen here there doesn't look to be anything that would keep me from going forward with this.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

At this point what I think you need to do is get a head gasket on it and do a compression check. Before all else.

I just recently picked up a 1975 50hp Johnson that was in unkown condition. Came off a scrapped boat. 1st thing I did before buying it was to do a compression test and then a spark test. Compression was 150lbs on both cylinders but no spark. After further inspection and the compression readings I'd gotten I paid the man the $100.00 and loaded it into my truck. After spending a little time on the electrical and finally getting good spark I put some fuel to it and it started right up. Did I get lucky? Maybe!

Again, from what I've seen here there doesn't look to be anything that would keep me from going forward with this.

I'm pretty sure you're right. The only reason I had for pulling the head was the broken bolts in the cover and the angle iron ignition coil mount made me wonder if anything else wrong. I'm glad I did pull the head though because that clogged water passage and the thermostat made me wonder if it did have an overheat problem. Seemed to have good compression when I jumped the starter, but I'll wait until I get the solenoid.

I'm still trying to figure out how to unblock this water passage. It's blocked in pretty thick. Any ideas? I'm trying to grind it, but I'm worried about hitting the mating surface between the powerhead and cylinder head since it's right there.