I Got Me a Mercury !!!

[tpenfield]

You got my nomination for the ugliest dingy I've ever seen.

Yes, ugly works . . . it is kind of an anti-theft feature.

 

[redneck joe]

Yes, ugly works . . . it is kind of an anti-theft feature.

That's why I've never been kidnapped, ugly and poor....

 

[Willyclay]

"it started on the first pull. "

Attaboy!

 

[tpenfield]

Here are the remains of the 1969 Merc . . . as I have taken off the stuff that is functioning/usable.
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[tpenfield]

The new(er) (blue label) Merc is not feeling well today. I was going out to the big boat, but the Merc 7.5 had other things in mind. I think the ignition is intermittent. I'll have to do some more testing to see for sure. I tried starting fluid, new spark plugs, but nothing. Last time out must have been a fluke.

While the Blue Merc is being diagnosed, I'm thinking of picking up a 2 cylinder 4 (ish) HP JohnnyRude engine. My other motor . . . the little 3 HP Yammy really does not run all that well and it has its own set of starting issues. It is a one cylinder, and does not idle well. I think single cylinder engines are not meant to idle down low, unless they have sizable flywheels. I've noticed that with outdoor power equipment . . .1,200 RPM idle is about all you can get.

Meanwhile the toolbox will be open for the Blue Merc. . .

 

[racerone]

A 6 HP Johnson / Evinrude from 1966 to 1979 are ideal.----The 66 to 76 used the universal ( low cost ) magneto.-----Need to know how to clean breaker points on occasion.----The 77 to 79 had electronic ignition.-----These are just wonderful motors if in good condition.

 

[redneck joe]

That was always dad's kicker on any boat he had, even the 25' cruiser. I had one for a bit as well, perfect.

 

[tpenfield]

I have a 4.5 HP Johnson from the 1980's (maybe 1984) . . . but it is a long shaft. It was a bit finicky when I first got it, but now it runs pretty well.

Maybe find its short shaft cousin.

My plan is to go through the Blue Merc's ignition system, test the coils, replace wires, etc. It would be nice it I could have it as my go-to motor for a while.

 

[tpenfield]

My game plan for the Blue Merc is to pop the flywheel off and go through the ignition stator wiring, replacing sections of wire as needed. Since the motor actually worked for me on several occasions, I am thinking that the problem may be with connections vs. bad coils.

 

[tpenfield]

I'm on my way to CA and will be there for 2 weeks. Plenty of time to read up on 'Phase Maker' ignition systems, which I believe is what Mercury has in these early-1970's motors.

 

[nola mike]

The new(er) (blue label) Merc is not feeling well today. I was going out to the big boat, but the Merc 7.5 had other things in mind. I think the ignition is intermittent. I'll have to do some more testing to see for sure. I tried starting fluid, new spark plugs, but nothing. Last time out must have been a fluke.

While the Blue Merc is being diagnosed, I'm thinking of picking up a 2 cylinder 4 (ish) HP JohnnyRude engine. My other motor . . . the little 3 HP Yammy really does not run all that well and it has its own set of starting issues. It is a one cylinder, and does not idle well. I think single cylinder engines are not meant to idle down low, unless they have sizable flywheels. I've noticed that with outdoor power equipment . . .1,200 RPM idle is about all you can get.

Meanwhile the toolbox will be open for the Blue Merc. . .

Get a DVA. Or you might want to build one. Not sure what type of electronic ignition is in that one, but I had a hell of a time last year chasing down an ignition problem on my 25 hp. Intermittent weak/no spark. I fired up the parts cannon to no avail, but having the DVA would have saved me a ton of time. Check out this thread:

'04 Merc 25hp dead(ish) cylinder

Been chasing some poor running for the last few weeks. Originally was running well, but had a couple of episodes where it died at speed, difficult to restart. Noticed fuel leaking from somewhere around the carb. Rebuilt the carb with a crappy kit. Took it out once and all the gaskets...

forums.iboats.com

 

[tpenfield]

Thanks @nola mike . . . The engine has what is known as a 'phase maker' ignition, which I believe was a lead-in to the electronic ignitions.

Basically the stator creates fairly high voltage and instead of 'breaker points' to fire a spark, it uses the opposite 'maker points'. I'll be going through it over the next few weeks. CDI has a nice write-up on the system and how to trouble-shoot it.

Probably will start a new thread dedicated to the 'phase maker' . . .

 

[nola mike]

You got me interested. Seem s like it's still closer to a CDI type system than a points system electrically. This is the most in-depth explanation that I found, though the writing is a bit dramatic:

https://wrcoutboards.org/wp-content/uploads/2021/02/The-Phase-Maker-CDI.pdf

Also, you probably came across this:

1971 Mercury 7.5 Phase Maker Learnings

I thought it would be useful to post a few of my learnings on the 1971 Mercury 7.5 Thunderbolt ignition system --known as the phase maker. I've learned a ton from this site over the years and am hopeful some info I gathered might be useful to others. Background: A few of years ago I bought a...

forums.iboats.com

 

[tpenfield]

I found that document that shows the connections, how to test, etc. My understanding is that there is a base plate (usually red in color) that has some electronics embedded into it. If those fail, it can be a show stopper.

 

[tpenfield]

Quick update . . .

I pulled the Mercury back to my house and began to disassemble the ignition system. It probably will take a week or 2 to go through everything and make it all good.

As a stop-gap measure, I picked up this 6 HP Evinrude to use while the Merc is 'under the knife'. Some guy had it in his basement; I tested the compression (60 psi - a bit low), and the spark . . . (very good spark). Cash on the table and brought it home.

The model # (6804B) maps to a 1978 model, but the cowling seems to have 1977 decals. E'rude/Johnny experts, please feel free to chime in.

Anyway, a couple squirts of starting fluid and it got going and could maintain a heart-beat on its own. I ran an intoxicating dose of fuel system cleaner and then did the Seafoam thing through the carburetor . . . The test tank filled with carbon and the motor smoothed out.

Anyway . . . I'll put this on the dinghy this weekend and see how it does in real-world conditions.

 

[DeepCMark58A]

Please just put mixed gas in a spray bottle and shoot that in the carb instead of starting fluid.

 

[tpenfield]

Quick update . . .

The Evinrude is now on the dinghy as is working fine. Not as smooth a runner as the Mercury, but it runs and has decent power.

As for the Mercury . . . I started replacing wires . . . lots of brittle crumbly.
I dis-assembled the stator and tested the ignition module plate thingy (red module) according to the CDI literature. It tested out fine . . . replacements, if you can get 'em, are $100+
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The '-' wires leading to the coils were quite brittle and the insulation was cracked. So I suspect they were shorting out to the casing. I removed the maker points and the insulator blocks have some cracking. New ones are on order. The crumbling coil wires are $42+ each !!! . . . . Not going to send upwards of $100 on a couple of wires. So, I'm going to use some marine wire that I have on-hand and salvage the fittings from the original wires.
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The green wires to the '+' side of the coils seem to be fine. Perhaps they were replaced along the way.

The maker points look OK. So, I'll be working on the ignition wires and waiting for delivery of the isolator blocks.

 

[Willyclay]

So, I'm going to use some marine wire that I have on-hand and salvage the fittings from the original wires.

Attaboy!

 

[tpenfield]

Here is my handy work, saving about $100. These wires have threaded studs soldered on one end and the ring connector on the other. They connect the maker points to the the '-' side of the coils.
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I did not have the OEM brown & white color wiring, so red (brown) and yellow (white) will have to do. I made these from stuff that I have on-hand.

 

[racerone]

The EVINRUDE is a smooth runner if in good condition.------One issue with them is a weak head gasket when new.-----Replacement gasket ( SIERRA ) is improved with metal rings.-----May need to adjust slow speed mixture.-----I own many of these 6 HP models ( 66 to 79 ) and they are fantastic motors.----Easy to find new / used parts for them.