77 Johnson 85 Horse Ran great but then died no spark

[MRneatfreak]

Had this motor for about 4 months. Done alot to it covered in another thread of mine.

http://forums.iboats.com/showthread.php?t=539676&p=3700390#post3700390

It has 3 new coils, new plugs, new powerpack, new impelller etc.. Ran great for about 6 hours yesterday, we stopped at the marina and refueled, 5 minutes after leaving hit a rogue wave in the bay, one of passengers fell out of her seat, so I throttled back to idle, went to power up and it died. Thought that was weird, went back to neutral, it started again but after more thottle died in gear. It finally got to the point where it wouldn't even idle. So I intially checked/dumped the fuel/water seperator into an oil sock, didn't see a whole lot of water, then decided to drain the carb bowls just to be sure. Didn't see much water separation come out. It just cranked after that, with an occasional chug but nothing that would go back to an idle. I pulled each plug wire one at a time and using an old spark plug I had I checked all four leads for spark, and there was none. Didn't see any bad wiring. It would make sense that it had something to do with the timing advance, as it was idleing fine but upon full throttle it attempts to go but dies. So I played around with that but nothing. Ended up calling TowBoat US for a 40 minute tow back to the docks.

I started troubleshooting today, checked the black/white wire for volts with key on and off. In off zero volts, in on .9 volts. Not good right?

Then I checked the brown/yellow and brown wire for resistance and read 975 ohms this checks the stator. Any idea what thats supposed to be?

I haven't ever changed the stator, timer base or the charge coil, or the rectifier.

 

[MRneatfreak]

Re: 77 Johnson 85 Horse Ran great but then died no spark

I have the Johnson service manual for this year engine, but alot of the procedures call for the use of antiquated meters and test probes, that I don't have.

 

[MRneatfreak]

Re: 77 Johnson 85 Horse Ran great but then died no spark

This problem has shaken my confidence up with this boat.

Well I replaced the ignition switch, and rechecked the black yellow wire at the power pack that controls when the ignition is to be shut off by getting a ground through the ignition switch. And the voltage actually got higher with the new switch, it now gets about 1.1 or so volts, but with the key in on, and it should be getting zero. So I checked for shorts between wires/contacts at both sides of the red connector at the engine, and couldn't find any. I also cleaned up the ground points. Couldn't figure out why its getting power when no continuity is shorting across? I don't have a meggar or a time domain reflectometer so its possible I have a high resistance short somewhere. The ultimate fix would be to run a new wire to replace that black yellow wire from the engine to the control box. But for now I'm going to call it good.

So after all the wire troubleshooting, I hooked everything back up, and turned the key. It popped right off, and a flame shot out of the prop. I had removed the remote box power cable from the boat and was able to view the engine while turning the key. It runs?!? Not only was there the not the usual hard start, but the first crank it popped off. So here's hoping the ignition switch was faulty and providing a ground to the magneto during cranking when it shouldn't have been. Thus sending all my powerpack spark to ground.

If this problem every happens again I will know now to check that black/yellow wire, and remove it just to get back to the docks. *note* if you do this you will not be able to electrically de-energize the engine, you would have to choke it till it dies or cut the fuel supply.

I also am hoping that its not the timer base intermittently malfunctioning. And the reason its working now is becuase it has cooled down over night.

 

[MRneatfreak]

Re: 77 Johnson 85 Horse Ran great but then died no spark

I was doing some troubleshooting studying on this website:

http://www.boatpartstore.com/page30.asp

and it states my resistance for my stator wires between brwn/yel and yel should be about 500 ohms, mine is 975 ohms. Do you spose this is a major problem? Even though I got it running here in the driveway?

I need to do the power on checks for the 150v at the power pack, and the coils etc..

 

[MRneatfreak]

Re: 77 Johnson 85 Horse Ran great but then died no spark

Well I took it out in the water today, and realized that part of my problem again was that darn cable for the rpm advance was loose again. And that black/yellow wire was causing intermittent stalls. So on on the water I ran new wire to replace black/yellow wire that cuts off the engine, and had no more problems there. I also got the cable secured again. The problem with that was the throttle would advance but the timing wouldn't and the motor would die. Time for a new shifter cable. This is the second time I've had problems with it. Things get out of whack when I lock the motor up for trailering.

 

[CynicCE]

Re: 77 Johnson 85 Horse Ran great but then died no spark

Sounds pretty similar to what I've been dealing with on my 75 135. I had no spark on any cylinders so I changed the rectifier (obviously bad wires), the power pack and coils. After those I got 2 cylinders back. The next step was to test the timer base by switching the wires and that's how I found out I had a bad sensor coil. I replaced the timer base so now I've got spark back.

FYI, all of my OHM readings checked in normal on both the timer base and the stator. I don't have the DVA adapter to test peak spark. I'd give a good visual inspection of the stator looking for goo coming out of the windings. That's a good sign that it's on the way out.

I didn't read super close but if you changed things one at a time and started with the power pack it's possible you burned that up too (which is why I grabbed everything in one fell swoop.) My manual lists these issues for an engine that will not start with no spark on 4 cylinders:

1. Sensor Coils
2. Charge coils
3. Power Pack
4. Key Switch
5. 10 way connector. (and let's be honest....this is a metal bar. As long as the grounds on each end of it aren't horribly corroded it's pretty tough for this to fail.)

Best of luck, let me know if there's anything else I can help with!

Ben