Technology revisited, the ignition energy w/o Battery

[Jerry_NJ]

I saw such a great response to the post on "technology" so I decided to include that in my title, it fits.

I have a 1997 9.9 hp, as you know no battery. I am having a no spark problem.

As this engine has an electronic ignition, it has a "Power Pack", there is, I assume, no magneto high voltage involved. Still, I assume the flywheel/stator has two ignition functions:
1) timing, when to fire the plugs
2) electrical power to power the Power Pack

So, when one pulls the rope, is electrical energy delivered to the Power Pack as well as a fire signal sent from a magnet on the flywheel?

I assume both plugs fire, only one being in the ignition/power stroke, the other piston being on the return/compression stroke. Is that correct? I guess that has nothing to do with my question..but interested any way.

As posted earlier, my dual coil has 0.28 ohms to ground on each coil, measured with the spark plug wire removed. The signal wires (one orange with a blue trace, the other solid orange) terminals on the coil housing both measure continuity to ground (wires removed)... I assume that is a problem. I add this as it is the reason for my current interest in the ignition system, for which details schematic information seems unavailable.

Can someone who owns a 1996 or newer 9.9 Evinrude find the time to measure the resistance to ground on the 4 terminals on the coil assembly - or simply tell me where to find it, or just what it is from knowledge?

Thanks

 

[wilde1j]

Re: Technology revisited, the ignition energy w/o Battery

You can buy a shop manual from any BRP Evinrude dealer or try Ebay.

 

[F_R]

Re: Technology revisited, the ignition energy w/o Battery

You are smarter than the average bear and have it pretty well figured out. Almost.

Let me start off with a disclaimer. 1997 is too new for me, but I am familiar with the older ones, which I have to assume work the same way. So, here goes:

There is a "charge" coil under the flywheel. "Charge" in this case means charge the power pack, not battery charging. As the flywheel magnets pass it, about 300 volts is generated in the charge coil and that 300 volts charges a capacitor within the power pack. Next, there is a sensor, also under the flywheel. As the magnets pass it, a small voltage is generated and applied to the power pack to tell it that it is time to fire. The power pack then discharges that 300 volts through the primary winding of the ignition coil, which acts like a transformer boosting the 300V to whatever it takes to jump the spark plug gap. Then it is all over till the next time.

SO, to answer your other assumption, no they do not both fire at the same time. The nifty secret to make that happen is the sensor output is positive in polarity as one magnet passes and negative as the other magnet passes, due to the north and south pole arrangement of the magnets. The power pack senses that polararity and only discharges to the appropriate coil.

All this is applicable to the older motors that have two coils. I ASSUME the new dual coil is the same, just two coils combined into one box. I stand to be corrected on that, if I am wrong.

The resistance of the coils is very low, especially the primary. That would be close to zero ohms. Not to be confused with old fashioned coils with several k-ohms on the secondary.

 

[jtexas]

Re: Technology revisited, the ignition energy w/o Battery

right, stator contains both a charge coil and a sensor for spark timing.

you can find the resistance and other specs in the troubleshooting guide at www.outboardignition.com

 

[Jerry_NJ]

Re: Technology revisited, the ignition energy w/o Battery

Thanks, and yes the 1997 has a dual coil in one encapsulated package, each is separate and the grounded side of the two coils (primary and seconday) are joined when the unit is bolted to the engine, the common ground.

The manual calls for a primary of less than one ohm, hard to measure with my equipment, but I think I saw a tenth or two and concluded that was a good sign.
The secondary at 225-325 ohms and both of mine checked out. I am not convinced that proves the coils are good.

I also checked the Sensor winding and got 40 ohms and the Charge winding and got 900 ohms, just a bit over the speck. I tried to get a voltage indication using a normal RMS AC meter and got a reading of 20 on the Charge and less that a volt on the sensor... I think this indicates the winding are likely good. I also checked the Kill wire and it is open to ground until I operate the kill switch, then it shows continuity to ground, as it should.

I do not have the equipment to do a high voltage test on the coil and will either find a shop that will do it for a reasonable charge, under $20, or maybe just buy a new dual coil at about $40 delivered. As for the power pack, I haven't decided how to test it but as the failure scenario for this engine involved several runs at a lake where it started fine but would not develop power, maybe no more than 25% of full power., about what one might get from running on one cylinder I think. During those times I was focused on cleaning up the fuel system. Finally late this year, and only my second trip with the first one being a repeat of the low power then full power of last year, it failed and would not even start. Checking I found a spark (air test) on the first pull, then nothing - this occurred several times if I let the engine sit for a few hours before trying again. This really sounds like a coil(s) with a high voltage breakdown, first on one coil, then after perhaps 10 hours of operation at full power (the story is in the beginning when ran at the poor power level for 15 minutes the engine would suddenly kick in to about full power - that's another reason I figured dirty fuel system). It wasn't until I couldn't even get the engine to start, beyond a couple of cycles on a first pull, that I decided to check the ignition.

 

[Jerry_NJ]

Re: Technology revisited, the ignition energy w/o Battery

I made a "home made" DVA adapter - see my post today on "Need a DVA adapter - make one for $5". - guess as the subject, I'm sure it is close to right.

I used the DVA adapter to confirm the Charge and Sensor coils are delivering the correct voltages to the Power Pack, then I confirmed that there is nothing coming out of the Power Pack on the primary drive leads (the SCR, Capacitor discharge path to fire the associated plug via its coil) - read open circuit.

I'm now thinking of buying a new Power Pack (can get for under $100, I believe) but a bit reluctant because of the cost... still not much compared to taking the engine into a professional mechanic.