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No Stat Ns90

Rvdv

New member
I have a late 80’s NS90 that has performed flawlessly for the last 30 some years. The other day it wouldn’t start. Using the FSM I went through the flow chart and did the recommended testing. The stop switch, exciter coils, pulser coil all checked out ok, the resistance values and voltage outputs are all within spec. I am using a external DVA adapter for my tests. When it came to the last test which was checking the CD output I got a reading of 90 DVA on all three outputs which is below the spec of 130DVA. I left the plugs in the engine to do this test. Before I order the the CD unit I wanted to check with the experts to see if I missed anything else that should be checked. Also, I am in Ontario, Canada, can anyone recommend a place where I can order this part?
 
I would double check all grounds, and also run the DVA output check of the CD with the plug wires disconnected before you order
3B7061602MC.D. IGNITION UNIT (F8T20571/8508)$387.42

which you can get from any dealer, including me. I am in Buffalo, NY, so can ship to Canada easily.
 
Ok, all grounds ok, checked DVA output with plugs disconnected, 120 DVA on all three outputs. Next checked the coils all 3 primary ok, secondary on all three is open, so I’m thinking coils. Paul could you pm me with your contact info. Will need to order parts.
Thanks
 
No spark, sometimes when I check for spark, I might get 2 or 3 sparks and then nothing. If I put an inline spark checker the orange light does flash indicating a spark, it doesn’t tell me the intensity though. I made adjustable spark checker as well and tried differant gap widths as well, no spark. The thing that puzzles me is the engine ran Perfectly fine, next day it started, ran for 5 seconds and shut down, so how can 3 coils be bad?
 
Rechecked exciter, resistance in spec, DVA calls for Min 130, I have 180. I also rechecked everything else according to flowchart, checked continuity of grounds right to battery, disconnected brown wire at CDI box to make sure that safety/stop circuit was working, still no spark. Now I have 128 DVA coming out of CDI box using 2 different meters. Logic to me says coils, but all three at the same time, that is not logical. I measured the secondary of all three coils with 2 digital meters and 1 analog meter, got open circuit reading on all three meters.
 
If you're in Ottawa, I have some could you could swap on to see. I'm also fighting spark issues, but only on #2 cylinder and I know my coils are good.
 
Thanks for the offer, but I’m in Toronto, boat is at cottage north of here. Anyway I have a coil to try later today, looks promising because I get a reading on the secondary on this coil, where I got open on all three that are on the motor now, fingers crossed. Did you check the pulser coil for cylinder#2?
 
The coils do cross to a bunch of applications including Yamaha outboards and 3-wheelers so hopefully you can find one for testing. If you're getting that good of a pulse from the CDI on all channels, that seems pretty convincing...

For mine, I'll start a thread if I can't figure it out, just working through the diag now.
 
So it turned out that my Yamaha had the same coil, swapped it out, same problem no spark. So I got a spare lawnmower spark plug, plugged it in, lots of spark. Went to Canadian Tire bought 3 new plugs, installed them, motor fired up instantly. Another illogical scenario, 3 plugs all gone at the same time? Anyway learned a lot about the engine these past 2 weeks. Thanks for your time to try and help me with this problem Paul, and thanks to LundProV for offering the coils.
 
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