1982 Johnson 90 hp - no sparks for 3 of the 4 or 4 of the 4 cylinders - please HELP

[ib18]

ok, thanks for your suggestions earlier - http://forums.iboats.com/forum/engi...82-90hp-johnson-outboard-won-t-start-plz-help
I was busy fishing winter bass (19" Monster bass) - https://www.youtube.com/watch?v=wPyWHCabjcE - and no time to fix the boat until today 30 degrees too cold to be outside.

I decided to troubleshoot my Johnson 90 hp outboard - 3 out of 4 cylinders got no sparks. I switched the 2 power packs and then no sparks for all 4 spark plugs. I think I have a short or ground somewhere - https://www.youtube.com/watch?v=FlAobp6COzg

 

[racerone]

Never used a tester like that and never will either.----------If starter / battery / battery cables are bad then motor will not crank fast enuff and there will be no spark.-------Test with all 4 plugs out and set up a gap of 3/8" and see if you have spark accross that gap.-----That is the only way and the best way to test for spark !!!

 

[achris]

If you still get no spark with ^^^ test, then you need to troubleshoot, and for that you need a DVA meter. You can either buy one (not cheap!) or make an adapter for an existing analogue multimeter (very very cheap, not so difficult).. Here's a thread from a LONG time ago, but it explains exactly how to do it.... http://forums.iboats.com/forum/engin...meter?t=374544

Once you have your meter you can satrt checking the outputs of the various components of the system. Start with the stator, you need to see about 300 volts on each side when cranking. Then check the trigger outputs, you need about 3 to 5 volts on each trigger coil. If they are good, check the outputs on the powerpacks. You should be seeing about 300-400 volts on each of them....

Chris.........

 

[emdsapmgr]

Racerone is right on target. If the engine won't crank at 250 rpm's it wont make enough voltage to fire the ignition system. That engine has these 4 ignition components: 4 coils, stator, timer base and 2 power packs. The 4 spark plug coils are pretty reliable and it's unlikely that all 4 failed at once, so: Start your ignition troubleshooting with the stator and timer base. You can qualify both of them with a "peak-reading" voltmeter (mentioned above) according to the techniques found at this website: cdielectronics.com. [The cdi advice there is superior to the factory manual back in 1982.] Look to test for out voltage on both devices when cranking over at 250 rpm's. The stator may qualify around 150 volts, the timer base perhaps 0.3 volts. Check the website for exact voltages. If you qualify both components, then I'd purchase one power pack. Retest for spark. Possible you may need the second one too.

 

[Joe Reeves]

The type spark tester that you picture using doesn't really tell the tale. You need to use a open air gap spark tester whereas you can actually set a gap of 7/16" for the spark to jump across. The spark should be a strong blue lightning like flame... a real SNAP!

The spark plugs must be removed in order to obtain the highest cranking rpm. The engine must crank over at least 300 rpm in order for the stator under the flywheel to energize the powerpack.

If the engine cranks over fast, as requirements stated above, but the spark still remains faulty... check the extreme forward and extreme rear portion of the stator. On that model, those two areas would contain the large coils that provide approximately 300ac volts to the powerpack capcitor. Should either of those areas be cracked and/or leaking/oozing a sticky looking substance down on the timer base and powerhead area... replace the stator.

Let us know what you find. No open air gap spark tester?... build the following.

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

 

[ib18]

Thanks for everyone's first class HELP. I found the cdi troubleshoot document, so I tried Step 2 above and disconnected the 2 yellow wires from the rectifier to the stator under the flywheel. https://www.youtube.com/watch?v=drA0O9RokFI - Bummer, still no sparks.

I will make a diy DVA meter and proceed to 3, 4 and 5 below next week.

 

[Bosunsmate]

If you have a multimeter just try the resistance checks as is. Often they will show up a major fault in the stator or timing base and save you making a dva.
My multimeter cost $8

 

[Bosunsmate]

I would suspect your stator so start there and also check its not shorting to ground. the wires get corroded and worn where they twist as the timing is advanced.retarded. They can short out there to the crankcase.

 

[Bosunsmate]

The stator is the brown to brown yellow 450-550 ohmns. If a stators bad the resistance is often non existence ie infinity ohmns

 

[ib18]

I think your guess of stator is probably correct. As I was checking all the wires for possible short and grounding, my buddy and I did find some stick fluid like crud. I think the stator may have melted. Bummer, I won't be able to find out until weekend. Bummer, it will cost me $200+ for a used one and $300 for a brand new one.

will keep everyone posted soon

 

[ib18]

Fixed by cleaning the ground terminals for all 4 ignition coils. now, getting sparks. will try start the motor soon. Thanks to all who helped.

 

[ib18]

Johnson 90 hp 2015 cold and first start - yes and finally motor is alive and kicking again. But the water peeing out of the hole was too hot, time to change impeller.