1972 Johnson 100HP Capacitance Discharge Ignintion power issue

[jbch]

Hello,

I have been restoring my families boat thats been sitting in a garage for 17 years. Thankfully, I have it running, but haven't taken it to the lake yet. I have done all the maintenance and restoration to the fuel and electrical systems, and have replaced several parts including the rectifier and pulse pack with the new CDI models. I have read on this forum by many, including Joe Reeves, that is very important to have a good strong battery and voltage to this powerpack to eliminiate the posibility of damage. I happen to be checking voltages and discovered that with the battery connected and the key turned on, I have 13 volts to the red wire on the wiring block but only 9.5 on the purple wire terminal where the power pack connects. I disconnected the power pack and then have the full 13 volts. Is anyone familiar with something like this? I submitted a question to CDI and they suggested that I might have a loose connection in the control box, so I went through it and cleaned/polished each connection with no change. The motor starts and runs well, but with as much as these parts cost, I want to make sure everything is operating in top condition.

While testing it in the water tank the other day, I noticed that I randomly hear clicking/arcing for a brief moment. I havne't been able to determine where its happening, and was wondering if I should replace the spark plugs, as they are the originals? The distributer tower/cap and everything under the flywheel looks good.

Any advice, suggesting are welcome.

Thanks.

 

[Willyclay]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

First, welcome to the forum! The experts here which I am not can help you solve any problem. However, I did have a similar experience with an older Johnson V4. The inline 20AMP fuse holder had corroded wires that was hidden under the insulation and checked okay for continuity but would not allow the full voltage to pass. Just about drove me crazy until I found it and replaced the fuse holder. Good luck!

 

[jbch]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

Yesterday, I got out and visually inspected all the wires in the wiring harness on the engine and found no visible problems. I even removed the old electrical tape and re-taped the whole harness. Is there a way to do a load test on wires? I put it all back together and it still only shows 9.5 volts with the key on, on the purple wire with the CDI ignition hooked up. The red wires on the terminal block show the full 13+ volts. With the ignition removed, the whole 13+ volts is present. This has me scratching my head. The moter starts, and I tried to take a voltage reading with the engin running but the cheap little digital meter goes crazy when moved close to the engine, is this normal, or is my electrical systems screwed up? Bench testing with the battery disconnected indicates everything is good. Stator continuity and ohms, rectifier good, no shorts, etc.

Occasionally I still here the clicking sound like one of my wires is arcing to ground, and the motor lags down while clicking, but I moved them around as the engine was running and it didn't seem to make a difference, the only thing that did seem to make a bit of difference was to move the timing advance lever a bit. Can incorrect timing cause the clicking? I haven't yet hooked a timing light to it to check it. I assume Joe Reeves method of setting the timing when cranking, will work with my engine and that battery capacitance discharge ignition system?

I'm sooo close, if I could just get the last gremlins worked out!

 

[Willyclay]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

and I tried to take a voltage reading with the engin running but the cheap little digital meter goes crazy when moved close to the engine, is this normal, or is my electrical systems screwed up?

The spark plug wires should be solid-core, tinned-copper that us old geezers refer to as Packard 440 wire. Unlike automotive plug wires, they have no RFI shielding and may create a lot of interference. My guess is that's what you are experiencing with the meter.

The link below is a recent thread by another forum member who has been battling the same problems with his motor of similar vintage and design. While he does not give a lot of details, he did get it running smoothly. Maybe there is a clue in it for you. Good luck!

http://forums.iboats.com/showthread.php?t=560580

 

[jbch]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

Well I have been working trying to figure out the arcing, causing the lag. I talked to the local boat place, who is very familiar with these old engines, and he said it might be a plug wire boot, so I got some new ones, and replaced them all. Unfortunately that didn't seem to make a difference. After removing the old ones, they seemed pretty good. Tonight while running it, I finally determined that it seems to be arcing up on the distributor tower of plug 1. I really didn't wan't this to be the problem, since new distributors/rotors run around $300 bucks for these old engines. I took the flywheel off and inspected it last night and didn't see any visible issues/cracks, so I'm not sure why this is happening.

I was also messing with the red wires connected to the starter solenoid/battery, and for a brief moment I was able to measure the full 13 volts at the power pack, but it shortly went back to 9.5. I moved the wires, took them off and reinstalled them, and still couldn't get the 13 volts back. All the wires on this motor seem to be in pretty good shape, there all soft and well insulated, so its making it very difficult to determine if any are bad.

One follow up, to my comment about the meter. I dug out an old analog meter and was able to measure voltage with the motor running and it seemed closer to 12v than the 9.5 before starting.

I'm hoping to take it to the lake tomorrow, for its first lake test. I'm afraid the arcing problem is going to cause it to run rough, but I'm desperate to try it.

 

[F_R]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

Arcing at the distributor cap towers where the spark plug wires enter was fairly common on those motors. There was a service bulletin on that. The cure was to remove (it unscrews) the wire and test the continuity, and if it passes put some grease in the tower boot.

Low voltage when a component is connected but normal voltage when disconnected is a result of resistance in the wire. That would be the TOTAL resistance of all the wire. In other words, from the battery to the key switch, the switch itself, and all the way back to the test point. ALL wire has some resistance, but what you are experiencing does seem a bit much. Oh yeah, I must say that the current draw of the unit you are disconnecting is the other half of the equation.

Just wondering, is the clipper circuit still there? I'm no authority when it comes to the CDI replacements, but it has been said that CDI says to remove the clipper circuit. You might want to verify that. The clipper circuit was there to protect the original power pack from high voltage spikes. CDI may have built the protection in their power packs, I don't know.

 

[Willyclay]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

When F_R posts in a thread, I pay attention! He is one of those experts I mentioned above. Good luck!

 

[jbch]

Re: 1972 Johnson 100HP Capacitance Discharge Ignintion power issue

Ok here is the latest. First to answer a few questions. F_R, the clipper was removed log ago. When I first pulled the boat out of storage it had no fire, so as part of this journey I put the new CDI ignition system on. Before, it had a replacement Wabash pack on it. Something I noticed, it seems that when I first hook up the battery and turn the key on the first time, I hear the power pack click and the reading is around 12.5 volts, but after the motor has been started a measurement shows 9.5. I have measured the resistance of the wires, from the battery side of the starter solenoid, through the fuse back to the switch and back to the purple wire terminal (with key on), and it shows very little ohms, practically none. I thought I might hook a wire directly from the starter battery terminal to the purple wire terminal and see if I still see the drop, if so, it can probably be credited to the power pack. According to CDI, the pack shouldn't be drawing that much power, the service manual says 1.5 to 2.5 amps at high rpm.

Ok, now for the latest. I replaced the plugs with the more traditional type with the hook, rather than the surface mount, and that seemed to make the engine run more smoothly like it wasn't missing because of the arcing. So I took it to the lake. Unfortunately, at medium and high throttle, it bogged down and wouldn't even push the boat on plane, and when I would back off it would sputter and try to die. IT WAS FLOODING. So the question is, is the flooding because of the lack of good spark or because of a carburation problem? I almost believe that I may have a carb problem, because at idle it starts are runs pretty good, but when I throttle it up, it seems to miss and smoke alot. Also when I pulled the surface mount plugs, to replace them, they were wet with oil/gas. So maybe the missing is somewhat caused by a flooding problem.

I rebuilt the carbs, last summer, but this is the first time its run since, so maybe I have a problem with them. The only thing is, these carbs are pretty much fixed. They have fixed jets and there is no ajustment other than the four idle screws, which by the way, I'm going to have to find the fiber washers, because they move around on their own. When I rebuilt them, they were in pretty good shape, but I replaced all the parts included in the kit. I did not knock out those aluminum plugs, but I washed everything well and blew out all passages with the compressor. I also did not replace the floats, as the kit didn't contain any, however, I did check the adjustment according to the manual where you turn them upside down and set them parallel to the base. They are the black plastic type, I wonder if possibly they could be faulty and are allowing too much fuel in. What regulates the amount of fuel in medium and high throttle operations, other than the jets which are fixed?

I am really discouraged at this point and not sure what to check for. I can't figure out why I would have a flooding condition with fixed jet carbs, but I'm also not convinced I have an ignition problem either. The arcing I saw the other night, is really not a bright spark I could identify, it was more of a low glow of continuous flashing, around the towers. Oh, and I have put generic tune up grease in those towers, so there is some grease in them.

Thanks so much for the help, and discussion.