Looking for wiring diagram for 1974 Johnson 70 HB Triple 2 stroke.

[Frickinfrack]

Stopped getting spark on any cylinders, Happened all of a sudden. Engine sat for a very long time. Already rebuilt water pump, rebuilt carbs, replaced fuel pump, and replaced starter solenoid and spark plugs aw well. Was running well died after running @ mid throttle for about 5 minutes. Had to slow up for very small idle speed zone then got right back into it. was almost up on plane and she just died. No spark to any cylinder since. Have never messed with these so looking for a wiring diagram or some color codes. Maybe what should have power going to it with the key on. Any and all help would be appreciated. For those of you that read and helped on my other posts, this is on the 1964 Sunray we were given last year. Problems I was having were caused by crap in the power jets. Rebuild fixed the issue. Thanks for the tips!

 

[racerone]

For one thing 12 volts from the battery is not used to make spark.------The spinning flywheel energizes the ignition system.------Disconnect the black / yellow stripe wire on the CD module and test for spark again.

 

[Frickinfrack]

racerone Just did that. No change. I'm assuming you are talking about the black wire with the yellow stripe that goes into the watertight box on the right side (standing @ the back of the boat) of the motor below the exposed junction strip. It's the only one I saw.

 

[F_R]

What racer said, the key switch does not supply any power to the ignition system, only turns it off by grounding the black/yellow wire. In fact, you could unplug the big red plug and it would still run. But you wouldn't be able to turn it off. If I were to make a wild guess, I would guess one of the wires between the timer base and power pack is broken internally. You moved the timer base when you slowed down, and that's all she wrote.

 

[Frickinfrack]

F_R I keep forgetting it's got a magento/ alternator combo thing going on. Guess I'll take the flywheel off and break out the ohmmeter and look for weirdness or opens. Any tips on pulling it and/ things not to do?

 

[F_R]

Technically, it's called Mag CD.

You need a 3-bolt puller to get it off. Do not under any circumstances use a puller that grabs the outside rim. And you MUST use a torque wrench to tighten the nut to 100-105 ft/lbs when you put it back on. Guessing can get real expensive, real fast. Also, flywheel and shaft tapers must be clean and dry before re-installing.

 

[racerone]

You can take ohm readings on components under the flywheel without taking the flywheel off !!

 

[Frickinfrack]

F_R and racerone Thanks for the tips. Will check for opens before pulling and hopefully wont have to. Now I just need to find one of my many multimeters.....

 

[Frickinfrack]

Been a while but wanted to give an update. Finally got around to messing with her again. Was the "power Pack 3". Assuming that is some sort of an early electronic ignition or something. Changed all 3 coils and plugs before swapping it out. From what I can see there isn't much else to it. Taking her out tomorrow to test and run some Seafoam through her to get her all all clean and running tip-top. Idles smooth as Buttah now and fires right up. I want to thank everyone for the comments and ideas.

 

[oldboat1]

late to the party, but here's a scheme with a power pack 3 ('78 version): https://maxrules.com/graphics/omc/wiring/78-84_3-CYL_EL.jpg