Nissan NS18E2 no spark

[akoz]

Here's my problem aside from no spark. I bought a SELOC repair manual and I was following the procedures to check the magneto, CD unit and coil (single coil for 2 cylinders in my case). The problem is that the CD unit on the motor is missing a black wire, the one that is supposed to connect to the magneto. I found the black wire coming from the magneto and it was just sitting there, not connected, never had been. This motor is a 1998 18hp 2-stroke and you could eat off the insides and the wiring is as new. With this missing wire issue (confirmed online at the Nissan outboard parts web site), I don't know if I can trust my DVA readings. I'd hate to bring this to a mechanic this time of year and find out that it only needed a simple part. I checked out the kill switch, neutral safety, etc. so it's nothing that easy. Any advice would be greatly appreciated. Thanks, Al

 

[pvanv]

Re: Nissan NS18E2 no spark

"Here's my problem aside from no spark. I bought a SELOC repair manual"

That is indeed a problem. The aftermarket, "one manual fits all" books are at best decent doorstops. Around here, we use them as woodstove tinder during the cooler months, BTW. A Factory service manual, available at any Nissan/Tohatsu dealer is a wise investment, and can be your good friend.

Your ignition system is among the simplest of CD systems, and troubleshooting it is straightforward. The exciter coil (under the flywheel) (two wires in a sheath) sends a pulse to the CD as the magnet in the flywheel passes it. The CD shapes the pulse, and sends it (one wire) to the siamese coil, which steps it up to spark voltage. For purposes of ignition testing, you can ignore the alternator assembly, unless you feel that the alternator wires and exciter wires may be damaged and shorted together -- if so, check that out.

The CD also has a black ground wire, and a pair (black and brown in a sheath) of stop switch wires. The ground must be connected to the block (typically via a CD mounting bolt), and the stop switch wires must be open-circuit for the CD to fire.

So the CD box has a total of 6 wires -- a pair for the exciter, a pair for the stop switch, a ground, and the lead to the coil. You can disconnect the exciter leads at the connector, and take a resistance reading on the exciter. Likewise, you can disconnect the stop switch, and take a continuity test on it. If those tests pass, you can test the CD output, and the siamese ignition coil. The procedures are in your Factory service manual.

 

[akoz]

Re: Nissan NS18E2 no spark

Yes, I had my doubts about the SELOC so I cross-referenced to the Nissan factory web site and their wiring diagrams agree with SELOC.

I did go through the static resistance tests for the CD unit and it fails. For example, red (exciter lead) to black (stop lead) should be about 4K ohms, but I read infinite (open circuit). I'm supposed to see about 4K ohms from the red exciter lead to gnd lead, but I read 150 ohms.

Again, I didn't trust these results because of the "missing" black lead that is shown going to the exciter along with red and blue. Also, the exciter has the "extra" black lead and it is not connected. I'm ok with assuming that this is another gnd lead and both the exciter and CD are getting a common gnd to the block, fine, but I don't know that for sure.

Oh, by the way, I contacted my local Nissan service place looking for a factory service manual and I was told to get the SELOC because the factory manual was "in Japanese". Based on that comeback, I thought that I might be on my own with the next nearest place very far away. I'd only use this guy for ordering parts...hopefully the correct one.

Thanks.

 

[akoz]

Re: Nissan NS18E2 no spark

sorry, one more important thing that started me rethinking these resistance tests is that I first went right for the exciter. BUT, the resistance test was for the black lead (not connected and missing at the CD) and the red. Since I only have red and blue to the CD, I don't have a resistance number for that.

I'm confident that there are no shorts and that the wiring overall is in excellent condition. Also, the lanyard stop switch is good (there is an open circuit to the CD when installed) and the neutral safety is good.

 

[pvanv]

Re: Nissan NS18E2 no spark

Hmm... What website are you calling the "Nissan Factory Website"? Service manuals are copyrighted, and should not be posted on the web. AFAIK, the only manuals available at http://nissanmarine.com/ are owner's manuals. Elvin does have parts catalogs at www.internetoutboards.com, but those manuals don't have test procedures or values -- just parts.

The exciter coil leads are red and blue, so you would use a good analog ohmmeter to read the at-rest resistance of the exciter. Some of the newer digital ohmmeters do not have enough drive to the circuit under test, and will read false high impedance, BTW.

Our shop's copy of the Factory service manual is not in Japanese. Perhaps your dealer is either mistaken, not very forthright, or doesn't want to order one in for you.

To verify the source of that "spare" black wire, pull the flywheel. That way you can also inspect the intersection of the exciter and alternator wires to see if that looks OK. It probably is a ground lead. Black typically is. Of course, you can verify whether it is attached to ground at the breaker plate by reading resistance to ground.

Sounds like you probably found a bad CD. Verify your tests, and if you need one, you can order 3G2060602M C.D. IGNITION UNIT (CU2556) $279.32 from any Nissan/Tohatsu dealer, even me.

 

[akoz]

Re: Nissan NS18E2 no spark

My references to the factory manual was actually the factory parts ordering book. They contain exploded views and wiring diagrams.

I will pickup an analog meter. Any chance I can get a few of the static resistance values for the basic Coil, CD and Exciter checks?

Yes, my CD unit is CU2556. I'd be happy to order from you as long as I can confirm that this is my problem since that's a decent amount of money.

Thank you.