I Got Me a Mercury !!!

racerone said:

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.

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Yes, I got my Johnson 4.5 HP sorted out a few years back, and I think this motor (Evinrude) will take the same. It did play a trick on me yesterday on the way out to the big boat. Crapped out from fuel starvation. Not sure what happened, but the fuel line lost its prime. It took some time to get the line re-primed. Meanwhile, as we were floating adrift in the harbor, the Admiral asked where is the paddle? . . . My response "back at the house . . . "

I think the Evinrude may need some fuel pump maintenance.

As for the Mercury . . . I came across a tidbit of info somewhere (can't quite recall) that these isolator blocks (basically non-conductive mounting studs for the maker points) can/do develop cracks which allow the spark to jump to the housing rather than the spark plug.

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I'm not sure if that is fact or theory, but these blocks have some cracks, so new ones are on order ($9 ea).

Just solved an Evinrude 15 HP.-----Stalling repeatedly.------Before even looking at the motor I looked INSIDE the fuel tank.-----Pick-up hose on a cheap plastic tanh was loose and sucking air.----Easy fix.

I ran the Evinrude some more today (with oars in hand) . . . definitely a fuel starvation issue. I brought the motor back to the house to run it in the test tank. I replaced sections of fuel line with clear lines so I could see what is going on.

Essentially, the fuel is draining back through the fuel pump and when you go to start(re-start) the motor crankcase pressure pushes the fuel further back down the fuel line. If the fuel pump & carb are well primed, it seems to work, but the fuel pump is not able to create much pressure.

Anyway . . . a new fuel pump is on order.

It will be a race to see which motor . . . the Merc or the Evinrude gets fixed first

About the only thing that can go wrong is the fuel pump diaphragm.----I have about 6 diaphragms on hand to repair that simple little pump.-----I would never buy a new big $$ pump.-----And no I would not use an " amazon special " on these wonderful motors.

After much testing and tinkering, I figured a few things out on the Evinrude.

1) The fuel line connection at the fuel connector was loose (not sufficiently clamped), which allowed air to get into the fuel line. A hose clamp did the trick.

2) The fuel connector at the engine also seems to be missing the check valve, which is causing fuel to drain back while the engine is sitting. I'll have to order a new one.

I'll be putting the Evinrude back on the dinghy tomorrow, as I'm still waiting for parts for the Mercury.

OK, I'm not having any luck with the 1972 Mercury ignition (aka Phase Maker). I've replaced wiring, isolation blocks, tested the module, the coils . . . everything seems to be per spec (Referencing the write-up by Bill Mohat) .

I am thinking that maybe I should just take the magneto ignition that I have from the 1969 motor, install it on the '72 and run it as such.

Could I just be missing something about the Phase Maker ignition?

Also . . . CDI has a troubleshooting guide, which I have been referencing for testing. There is one more thing I can try . . .maybe it will will work

Have you used a DVA? A typical dvm doesn't have the resolution to see what's going on in an AC CDI ignition. Phasemaker ignition seems electrically similar to a modern CDI, just with some mechanical parts as well. Haven't seen where you've replaced the pickup coils on the stator

I need to see if I have a DVA . . . I'm only getting 20-25 volts from the stator using a DVM. I should be seeing 180v P-P from the stator.

I have an oscilloscope, which should do the trick to read peak voltage.

I went back through all of the tests specified in the CDI literature. Here is my test results . . . See the values written in . . .

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Everything looks good except the peak voltage from the stator (CDI calls it an alternator). I am only getting 110 - 140 volts . . . maybe some as high as 160 volts. This is with no spark plugs in so the flywheel is going pretty fast. The test spec. calls for 180+ volts, so it is a bit light.

The actual wave form looks like this . . .

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I think the smaller wave is from the high-speed coil and the large wave is the low speed. I'm also thinking that the voltage wave looks fairly sharp, there is supposed to be a capacitor to smooth it out and sustain it a bit.

Anyway . . . Right now the stator looks to be an issue, but each of the coils tests out OK for impedance. Got to think about this some more . . .

My next step may be to check the ignition coils to see if they are shorted or something . . .

Although, looking at potential replacement parts, starting to feel like . . .

tpenfield said:

I went back through all of the tests specified in the CDI literature. Here is my test results . . . See the values written in . . .
View attachment 409511
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Everything looks good except the peak voltage from the stator (CDI calls it an alternator). I am only getting 110 - 140 volts . . . maybe some as high as 160 volts. This is with no spark plugs in so the flywheel is going pretty fast. The test spec. calls for 180+ volts, so it is a bit light.

The actual wave form looks like this . . .
View attachment 409512
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I think the smaller wave is from the high-speed coil and the large wave is the low speed. I'm also thinking that the voltage wave looks fairly sharp, there is supposed to be a capacitor to smooth it out and sustain it a bit.

Anyway . . . Right now the stator looks to be an issue, but each of the coils tests out OK for impedance. Got to think about this some more . . .

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That's your issue. Are you talking pick up coils or ignition coils? Either way they can ohm out fine and still be bad. Idk what the wave form should look like, I'd think it should be sustained to give the capacitor time to charge (in my thread I mentioned getting an oscilloscope to test it). On my 2 cylinder the good one was 300+ v. The bad one was intermittent, which was of course why it was hard to track down. The bad cylinder would be 80v, and occasionally hit 100-150v which triggered the timing light and gave me a weak spark but didn't fire the cylinder. At 200v it did...

Thanks @nola mike

The schematic looks something like this, The maker points ground the 'spark' coils, the 'generator' coils provide the voltage source.
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I suspect that something may be dragging down the voltage, or the low-speed coil is not creating enough voltage. If I have to replace coils, it may get expensive.

I'll do some more testing, but I have the magneto ignition from my 1969 motor ready & waiting.

Quick Update . . .

Rainy day, so I decided to do some more testing on the 1972 Mercury.
I Took the spark coils off and pull-tested the stator alone to see if I would get good voltage. Looks like I am getting 280 volt peak. (each division on the screen is 40 volts (I was getting the trace to go up 7 divisions)
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View attachment Merc-Stator-1A.mov
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I also checked the coil resistance and it seemed to be OK. I also noticed that the spark plug wire to the bottom cylinder is intermittent. I then connected the spark coils one at a time to see if I was still getting peak voltage. I did not mount the coils, just connected the primary leads and used a jumper for the secondary pigtails.

Under load, I was getting about 240 volts peak. I then connected my spark plug testers and was getting a light on each cylinder . . . Sometimes not on the intermittent wire.

I then connected spark plugs in place of the testers and was getting spark . . . not the biggest spark, but some spark. I suspected that the pigtail wires of the coils were not sufficiently grounding to the carrier . . . I soldered on wires and ring connectors to that they can be firmly connected to ground.
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Here are the results of the additional checking/testing . . .

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I was able to fix the intermittent plug wire. I also found some corrosion on the the spark plug wires and the coil receptacles . . . cleaned them up. So, I'm going to be putting the spark coils back on as they normally should be mounted and run some more spark tests.

Well it is a no-go . . . after all the testing and tweaking, it still does not want to fire a plug. The plug tester lights up and I am getting 240 volts peak, but there just does not seem to be enough to fire the spark plug to a reasonable extent.

I contrast that to the Evinrude that I picked up a few weeks ago . . . the spark was visible in daylight.

Next steps are to put the magneto ignition on it and hope it works.

tpenfield said:

Well it is a no-go . . . after all the testing and tweaking, it still does not want to fire a plug. The plug tester lights up and I am getting 240 volts peak, but there just does not seem to be enough to fire the spark plug to a reasonable extent.

I contrast that to the Evinrude that I picked up a few weeks ago . . . the spark was visible in daylight.

Next steps are to put the magneto ignition on it and hope it works.

Click to expand...

Man, I really want to see you get this thing going. I'd love to see what a proper oscilloscope trace looks like. I would think that you need more dwell to charge the capacitor. Was the capacitor itself tested?Also, did you put the scope on the generator coils directly? Red/yellow and blue/yellow? I'd imagine you should see a nice sine wave.

nola mike said:

Man, I really want to see you get this thing going. I'd love to see what a proper oscilloscope trace looks like. I would think that you need more dwell to charge the capacitor. Was the capacitor itself tested?Also, did you put the scope on the generator coils directly? Red/yellow and blue/yellow? I'd imagine you should see a nice sine wave.

Click to expand...

Yes, I'm thinking that the charge from the stator coils is dissipating too quickly, particularly when I tested it with no coils attached. That would point to an issue with either the capacitor or the electronics module.

One issue is that the parts for the phase maker ignition are rare and pricey, so it is expensive to start throwing parts at it. An example is the capacitor . . . Mercury & aftermarket parts are $50+, the coils are similar cost. So, the to load up the 'parts cannon' could end up costing $500.

I do have some capacitors, but they are way to much capacitance (2200uf) and not enough voltage rating. I might try to get a capacitor of the 'electronics variety' that more closely matches the Mercury spec.