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Nissan 9.8B 2 Stroke question

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Uglyduck

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I have a Nissan 9.8B 2 Stroke, and I am pretty happy with it. My wife and I are cruising the Bahamas and that little motor gets our big 10ft RIB, about 110 lbs, and us, about another 350lbs up on plane and moving about 12-15knts. In flat calm with no wind, chop or current. Starts easy, nice and light and runs good, most of the time. And there is where my question is.

Twice now she has left me in need of a tow back to the boat. But, a bit more about the engine first. I bought it lightly used, it had been put up for about three years. I bought a rebuild kit for the carb. Took the carb apart, to include pulling the jets and the emulsifier(?) tube cleaned it and replaced a few gaskets. rebuilt the fuel pump, replaced all of the diaphragms. New fuel lines and fuel filter and plugs. Ran like top, no problems always started, usually w/o the choke, and would run well. That was in December. About three weeks ago we went to shore and did some shopping and she wouldn't start, didn't even act like it interested in doing the internal combustion thing. We get towed back to the boat, I have a beer climb into the dink and tried to start it, and after a bit of pulling, she fired up. I let her run, shut it off, and then I started it right back, no problems. Did that a few times. Pulled the plugs and replaced them; not because they looked bad, just because I had replacements, Same with the fuel filter, which had some resistance to it when you blew through it. Put back together, pulled the string and she sang me the song of her people, pure and sweet. We declared our love for each other once more and forgave all.

Until today....
I grabbed my dog to take him to the beach for his walk, it was blowing 20 and the forecast said it was to increase throughout today so, it is now or tomorrow. Stopped by a friends boat on the way, maybe a 5 min slow run, just on plane. Chatted for 5 min and my cap blew off, started up and grabbed it up aaand she stalled on as soon as I got back to my friends boat.Talked for a bit more, handed him my bow line and pulled. And choked and pulled. And tilted my head just right, twisted the throttle and pulled. No love. It was like she had never heard of this internal combustion thing I was asking of her. Pulled the plugs, they were wet and smelled of gas. wiped them down, put them back. Changed the fuel filter and still nothing.
So, after I get towed back to my boat, again. I have a coffee with some Bailey's and tear into it. Disconnected the ground wire to the safety kill and, nope, not it. Checked wires and connections, all clean, tight and no corrosion. Drained the float bowl, filled it with the bulb, nothing. Finally, after this and that, I could hear her trying to sing out. And then, like nothing had ever happened, she sang out her unending love for me. Shut her off, fired her right back up. Connected the safety switch back up, all is working like it should. The only thing I noticed was there was a bit of black...oily stuff that came from the exhaust, presumably.

I felt like it was a spark issue, but now I'm not sure. Any advice?
 
Thanx! So the best/easiest way to do that in the field would be to pull a plug and look for spark? And I presume that there isn't a field fix to it; that it will require a parts swap. I would guess that the CDI would be suspect, not the pulse coil/magnet thing?
 
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If the plugs were wet, either it was over-choked, or there was no spark. Yes, you can pull a plug and ground it to see if it has spark. The spark starts with the exciter coil, which charges the CD module. In your case, the CD is integrated with the ignition coil. Any of those could have an intermittent failure. The problem is trying to recreate the fault so you can test. Also, if the inculation of the brown wire is compromised, and that wire is grounding, that will kill ignition.
 
Again, thank you. I will trace down all of the wires to and from the coil and make sure all is as it should be. Is there a trouble shooting procedure for the ignition system that can be done in the field with a multi meter? Also, and I know I could go look but its still blowing snot outside and getting in to that dinghy is bit of a rodeo ride right now, is the exciter a magnet/ coil on the flywheel set up that needs to be gaped?

Ted
 
Yes. You should get a Factory service manual to dx the ignition with an analog ohm meter. But, if it is running, it will probably pass testing. You need to have it fail and then test. The exciter is not adjustable for gap; it it is located correctly on the plate, it does not need any further adjustment.
 
Are the Seloc online manuals worth having? Again, I am in the Exumas trying to get this figured out and having a print manual mailed to me just isn't an option right now.
 
The aftermarket manuals are too general to be of much use. The Factory manual is the way to go. There is a dealer in Marsh Harbor.
 
I too have the exact same problem. It is not a fuel issue, the primer bulb is hard indicating there is no fuel starvation issue. The choke does not move to closed position on it's own while underway.
It must be an ignition problem, my guess is an ignition component gets warm and causes the problem, as the engine will start after it cools (after getting towed). It could be the CDI box, that would be an easy fix. The stator would be a not so easy fix.
 
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