1979 20 Hp Merc Two Stroke - Crumbling Harness

[Monmouth00]

Hello All,

I'm getting to the end of a restoration project, and was installing some wiring last night.

The harness was heavily taped by the previous owner, and I had noted before that some of the sheathing near the battery connections was cracked and flaking off.

In order to route it correctly, I needed to cut back where the PO had taped together the "Y" where the harness splits between battery and motor.

Unfortunately, when I did, I saw that there was also a lot of cracking and crumbling on the sheathing under there as well. Honestly, there was some full-on bare wire left after some of the insulation turned to dust in my hands.

I tape it up with multiple layers of electrical tape again, but I'm nervous.

Will I be able to get through this season with it as it is, or should I spend another $200 to replace it?

Thanks for your advice!

 

[GA_Boater]

Crystal balls don't work well when talking about old Merc harnesses. :smile: It may last another 10 years or 5 minutes if the unseen insulation flakes off while driving on the lake.

Most likely the wire strands inside what's left of the insulation isn't in such good shape either and will haunt you with funny problems until it dies on the lake.

If you plan on keeping the boat and or motor, it is worthwhile biting the bullet now and finding a new harness.

 

[Monmouth00]

So, question -

I was having engine trouble last year. I would get around the lake just fine, but after cutting the engine and anchoring for a while, the engine would sometimes start, but stall going into gear.

I assumed it was a fuel issue, and my engine repair guy just told me my faulty float valve was likely to blame.

But could this have been a consequence of a bad harness?

It doesn't seem likely to me, but I'm not all that familiar with outboards.

What do you think?

 

[km1125]

I'm guessing this is an electric start, if you have connections to a battery. I'd make sure those wires were taped good so there's no chance that the battery current could flow through a short and destroy what's left of the harness. That would make a mess.

Curious if you have any pictures of your motor? I have a similar one and I'm trying to nail down the year because I can't locate a serial number on it. I'm sure it's a mid-70s to early 80s, but would like to know for sure.

 

[Monmouth00]

Curious if you have any pictures of your motor? I have a similar one and I'm trying to nail down the year because I can't locate a serial number on it. I'm sure it's a mid-70s to early 80s, but would like to know for sure.

Here's the best one I have. Sorry, but the motor is at the shop right now, so I can't take another.

It's masquerading as a 9.8 because we're HP limited on our lakes up here. I'm fairly certain it's a 20 HP, and either a 1979 or a 1980.

I pick the motor up tomorrow after servicing. I'll ask my guru where to look and what might distinguish a year.

Thanks!

 

[km1125]

Here's the best one I have. Sorry, but the motor is at the shop right now, so I can't take another.

It's masquerading as a 9.8 because we're HP limited on our lakes up here. I'm fairly certain it's a 20 HP, and either a 1979 or a 1980.

I pick the motor up tomorrow after servicing. I'll ask my guru where to look and what might distinguish a year.

Thanks!

Thanks for the photo! Mine has the exact same two-tone blue stripe on the side, but above it is black instead of grey like yours. My front panel has the two-tone stripe on the bottom and the black on top. Very similar, but not exact. I'm guessing a year apart.

 

[Monmouth00]

Thanks for the photo! Mine has the exact same two-tone blue stripe on the side, but above it is black instead of grey like yours. My front panel has the two-tone stripe on the bottom and the black on top. Very similar, but not exact. I'm guessing a year apart.

Remember, mine is a 20 hp, but the stickers say 9.8

Someone obviously replaced them, and I can't be sure that they replaced it with the correct vintage decal.

Good luck!

 

[jimmbo]

Curious if you have any pictures of your motor? I have a similar one and I'm trying to nail down the year because I can't locate a serial number on it. I'm sure it's a mid-70s to early 80s, but would like to know for sure.

Serial number should be on the swivel bracket, and on a plug on the powerhead. Post a pic, a few of us can at least tell you what year the cowl decal is

 

[km1125]

Serial number should be on the swivel bracket, and on a plug on the powerhead. Post a pic, a few of us can at least tell you what year the cowl decal is

No tag on the bracket anymore. I have not found a plug yet on the powerhead, but I have not removed anything off of it so there might be one hidden underneath where I can't see it without some disassembly.

Here are a couple pics of the decals:

 

[Mohawkmtrs]

km:

According to nymarine dot ca, your decals are from a 1980-81 Mercury 20 hp.

 

[km1125]

km:

According to nymarine dot ca, your decals are from a 1980-81 Mercury 20 hp.

Thanks!