1996 Johnson 40hp No Spark

Status
Not open for further replies.

Zigblazer

Cadet
Joined
Apr 27, 2014
Messages
17
I am trying to help a friend with a boat they just bought. Model J40TTLEDS. I've searched and tried several testing suggestions, and most of the wiring colors they reference don't match what I have here.

Long story short it was purchased not running. I repaired a bunch of wiring, not engine related. I replaced the water pump, rebuilt the carbs and VRO. It didn't start, no spark. Checked the internet to see what to do that night. Pulled the black/yellow kill wire plug, fired right up. Checked all the connections, plugged everything back in, fired right up and it ran beautifully. Friend came the next day to test it out and take it home. Wouldn't start. No spark. Pulled kill wire, still no start. Checked connections, found a pin on left side of the engine, purple wire, not seated all the way. Pulled it in, figured it would explain an intermittent no start. It didn't.

Every diagram I've found has different color wires from what this engine has. They all show the main red plug, that I don't have. I'm not sure which wires to check when the colors don't match. Some resistances match, but the brown wires up to the stater have no connection. Resistance is OL. I might add, when I first tried to start it, I noticed the rectifier was hot and the flywheel was too, but the key was only on for a minute. And it hadn't ran.

If anyone has a diagram that fits, or can tell me which wires to check what on for the 1996 2cy 2st 40hp, please let me know.

Thank you.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
I think 96 was the first year without the red plug.---------Near impossible to give advice on 12 volts / wiring from 1000 miles away.-----You need a factory manual with wiring diagram.
 

ONERCBOATER!

Seaman
Joined
Oct 25, 2022
Messages
57
I Agree on the near impossibility of easily diagnosing from 1000s of miles away.
Most older outboard engines I have dealt with are shut down via grounding ignition systems. I would suggest checking fuses, relays, and my personal favorite which lead to an unusually long 20mile self rescue via kicker engine... damaged or pinched wires grounding ignition system.
That particular one for me was a wire rubbed bare on a 1980 Johnny 35hp under the cowl...and it only shut me down when exposed to saltwater not to fresh. It was hell to find.
But if the obvious stuff looks good start looking for less easily found things like pinched or grounded wires...

Hopefully this helps and please let us know what you find as the answer.

Sean
 

Zigblazer

Cadet
Joined
Apr 27, 2014
Messages
17
Got a manual. Searched for specific testing procedures. Came up with some inconclusive results. If I go by the readings I got, then I need a new stator, power pack, and coil. All resistances are within limits except for the coil, but cranking voltages are not. Charge coil resistance is OL to ground (which is spec), but produces around 30vac while cranking, spec is 0v. Charge coil resistance between wires is 763ohms (spec is 750-950), but only produces 211vac while spec is 250+. So that would indicate a slight problem, might not fire, then again it might. Signal coil voltage is 0.23vac with spec being 0.5v. That too is within the stator, and close enough to maybe work.

Coil primary input from the power pack measured 0.1vac with a spec of 150v. So power pack could be junk, or not giving correct output due to the charge coil voltage out of spec. And resistance across primary coil circuit lugs I thought was low, but forgot to write it down.

Anyone with experience please let me know what these readings would indicate. I don't want to make several orders replacing parts and just guessing.
 

Zigblazer

Cadet
Joined
Apr 27, 2014
Messages
17
After some more research tonight, I believe I can not trust my peak voltage readings. I have ordered a DVA adaptor and will test again after I receive that. With the exception of the 30vac produced while cranking where there shouldn't be any. I don't know if that would cause a no spark condition or not.

From what I've read, my meter on Max VAC will give a lower reading than through a DVA adaptor. So the 211vac I got might be good, and therefore should still allow it to fire.

All in all, I'd rather rebuild diesel engines and troubleshoot modern fuel injection system electronics. Every time I need to work on a 2 stroke, it is a pain in the rear.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
Fact-----Charge the battery.-----Have battery load tested , even if new !---Take starter apart for inspection , and ohm test on armature.----No money spent !
 

Zigblazer

Cadet
Joined
Apr 27, 2014
Messages
17
Got the dva adaptor. Using Vac is a completely wrong testing method. Vdc would have given me more useful info, but still been wrong. Ignore the people that say you can use a couple certain fluke meters set to max. I have one of the three listed and it didn't work.

Long story short everything tests out perfect on the charge coil and signal coil. No shut down ground signal to power pack, so it has everything needed to fire. Still no output from power pack.

I have ordered a new power pack and will let you know if it fixes the problem.
 
Status
Not open for further replies.
Top