1973 Johnson 85HP Cylinder Order

[Randyg123]

I need to confirm which cylinder is which on my 1973 Johnson 85HP (model 85ESL-73M). It has used head covers, put on due to stripped out spark-plug holes. These were off a different engine so the numbers are not correct on the covers. I found small numbers stamped on the heads as follows. Top Port (1), Bottom Port (2), Top Starboard (3), and Bottom Starboard (4). Is this correct?

The problem is my Power Pack does not jive with this arrangement. Cylinder 1 (as described above) goes to Coil 2 (Pin 3) on the Power Pack. Cylinder 2 goes to Coil 4 (Pin 5), Cylinder 3 goes to Coil 1 (Pin 10), and Cylinder 4 goes to Coil 3 (Pin 11 on the Power Pack). The Sensor wires appear to be correctly connected based on color coding and wire labels.

The engine runs but poorly at low speed. So first I have to confirm what Cylinder is what and the if the engine could run if the coil/cylinder discrepancies noted above do exist or are there other wiring changes elswhere to compensate for these, that I haven't found yet.

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

I have the same engine

starboard top is #1
starboard bottom is #3

Port top is #2
Port bottom is #4

should have a wiring diagram on your amplifier make sure the correct coil is attached to the correct terminal

Poor running at low speed could be ignition,fuel, or compression.

 

[ezeke]

Re: 1973 Johnson 85HP Cylinder Order

Following Wavrider's cylinder numbers, use the attached diagram for the wires.

Make sure that all of the ground wire connections are thoroughly cleaned. If the ignition coils are cracked, swollen, discolored, or appear even slightly melted, it is a good idea to replace them.

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

ezeke & wavrider - Thanks for the replies. It appears my powerpack connections are correct then. Why the conflicting numbers are on the cylinders I guess I'll never know! And yes I have two cracked coils (both Port side).

I've got many more questions but will end this post
Thanks again,
Randy

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

Randy,

Keep the questions running, that way we know what we are dealing with in one thread, as long as it is with your ignition keep it here and ask all the questions you want,

If you have 2 cracked coils they do need replacing, I replace all 4 of mine and keep the good ones for spares.

I spent weeks sorting out my ignition problems so I can pretty much remember the specs off the top of my head.

Also check your spark plug boots for rust, this can cause a major headache when chasing down ignition problems.

As far as the cylinders being marked wrong? Maybe some wrench marked them for his knowledge as far as wiring order.

YOu really need to have a DVA attachment for your DVM meter to fully trouble shoot this ignition system, you can build one from parts from radio shack for around $18 or purchase them for around $35 to $50 from various vendors, this meter allows you to see peak VAC from your pick up coils under the flywheel going to your amp, and also from the amp to your coils, without this attachment only thing you can do is ohm the pick up coils/

thay should be 8.5 ohms for perfect,,, 8 to 12 ohms will work, this is the trigger input wires, you will have two sets one on top of your amp and one on bottom of your amp coming from under the flywheel.

Keep the questions flowing until you get it figured out

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

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

Follow this link to your specific engine, lots of good troubleshooting techniques and info.

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

Randy,

YOu really need to have a DVA attachment for your DVM meter to fully trouble shoot this ignition system, you can build one from parts from radio shack for around $18 or purchase them for around $35 to $50 from various vendors, this meter allows you to see peak VAC from your pick up coils under the flywheel going to your amp, and also from the amp to your coils, without this attachment only thing you can do is ohm the pick up coils/

thay should be 8.5 ohms for perfect,,, 8 to 12 ohms will work, this is the trigger input wires, you will have two sets one on top of your amp and one on bottom of your amp coming from under the flywheel.

Keep the questions flowing until you get it figured out

Last night, I got busy with the DVM. Following my "Clymer Shop Manual" directions, I measured the resistance of the Sensor Coil and Charge Coil. Pins 2-4 - 8.6ohms, Pins 9-12 - 10.3ohms. Both to ground showed infinite resistance. For the Charge Coil: Pins 7-8 - 615ohms. Ambient temp was in the upper 70's if that makes much of a difference. According to the manual, my Sensor Coils should be between 7.5 and 9.5ohms; while the Charge Coils should be between 835 and 985 ohms. So the book recommends replacement of the Sensor Coil and Timer Base Assembly as well as replacement of the Charge Coils and Stator Assembly because of these out-of-range readings.

Would everyone agree to that diagnosis? Should I stop any further testing and replace those items ($$$$$) before going any further? Or are these values (albeit not great) acceptable and further troubleshooting should be conducted?

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

Randy,

As far as the cylinders being marked wrong? Maybe some wrench marked them for his knowledge as far as wiring order.

The numbers I was referring to are stamped into the block, down by the bypass covers. For all I know, one of the owners before put in a different powerhead or has mixed/matched components!!

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

http://www.boatpartstore.com/page40.asp

here is another great link for info on your ignition
including resistance readings

Read the measurements on the chart, they differ from clymer, your readings should be ok

Sems like you may just need some coils, if the amplifier is good

 

[ezeke]

Re: 1973 Johnson 85HP Cylinder Order

The cylinders are numbered from top to bottom in the order that the pistons attach to the crankshaft and starting at the top with number 1. It does not matter what numbers you find on the parts.

The cylinder heads have very small, upside down, raised numbers on the inside edge, though.

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

Randy,
YOu really need to have a DVA attachment for your DVM meter to fully trouble shoot this ignition system, you can build one from parts from radio shack for around $18 or purchase them for around $35 to $50 from various vendors, this meter allows you to see peak VAC from your pick up coils under the flywheel going to your amp, and also from the amp to your coils, without this attachment only thing you can do is ohm the pick up coils/

I can put that old electronics degree into play here! How do I construct a DVA?

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

Cool another tron chaser

full wave Bridge rectifier,

Use some rectifier diodes, 1n914 or similar
use a 10meg 1/4 watt resistor for bleeder resistor and a .5 or 1 microfarad capacitor for filter cap. i used metal type no need for eloctrolytic

the cap just keeps the charge to allow the dvm to read the voltage before the resistor bleeds it off

the leads connected to the dvm will be positive dc and negative dc accordingly

the leads that connect to the amplifier will be the ac input to the bridge

set your dvm on 500 or 1k dc volts
divide the reading by 1.8 to give you peak to peak ac volts

i used a set of meter leads and cut them, soldered the tip section to the ac input on the bridge

used the side that connects to the dvm on the output of the bridge of course black to - dc and red to + dc

you can even purchase a small project box at rat shack and a bread board to put the circuit in

works great

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

full wave Bridge rectifier,

Use some rectifier diodes, 1n914 or similar
use a 10meg 1/4 watt resistor for bleeder resistor and a .5 or 1 microfarad capacitor for filter cap. i used metal type no need for eloctrolytic

the cap just keeps the charge to allow the dvm to read the voltage before the resistor bleeds it off

the leads connected to the dvm will be positive dc and negative dc accordingly

the leads that connect to the amplifier will be the ac input to the bridge

Is the attached pic what you are describing. And is there any resistance required in series on the output?

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

Great CADD drawing

yes exactly

not really any need for input resistor, no impedance matching required, besides the dvm should have a resistive input circuit I would think, and there will not be any RF running around the outboard while performing measurements so up to you if you want a resistor inline, I did not install one in the one I built.

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

No CADD just MS Word Drawing scribbled out B4 I left work.

Just built my DVA but I used a rectifier instead of four diodes. Hopefully nothing else will be different.

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

Okay,

Hopefully my homemade DVA is working correctly.

Read 280V with wires still connected to power pack and 402V with them disconnected.

Divide by 1.8 and I get 155 and 223 VDC respectively.

Is this a hip-hip-hurray situation???

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

yes that is good measurements, so you are getting min of 150vac to power pack,, all measurements are with wires connected to amp,, now you can check the output of the amp going to the coils, the orange wires, there will be 4 of them, one to each coil,, should be if i remember correctly,, around 150vac or better to each coil.

if you have 150vac or better to each coil then guess what?????

weak coils are your problem,, or bad compression in the cylinder,,so check your coils voltage on the input and see what you get

this ignition is really a piece of cake once understood how it works

refer to the links and charts I gave earlier, I printed the charts out and inserted them into my manual for future reference

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

yes that is good measurements, so you are getting min of 150vac to power pack,, all measurements are with wires connected to amp,, now you can check the output of the amp going to the coils, the orange wires, there will be 4 of them, one to each coil,, should be if i remember correctly,, around 150vac or better to each coil.

Great news!
Okay for the coils. Do I measure between each coil wire (orange) and ground? Or do I choose a point on the powerpack.

That chart also had measurements to check out the sensor voltage (+0.5V) but I am not sure how to check those either. It looks like they are asking me to alternate leads between sensors [two black/black-white combos and two white/black-white combos]. Is this correct?

 

[wavrider]

Re: 1973 Johnson 85HP Cylinder Order

the coils

you can go from one orange lead to ground with the probes, ac voltage, the one going to the coil on the orange wire put red meter, the black to ground
of course you will only be reading the positive protion of the ac sine wave but it will work should give you around 280 dc or higher

I would do the coil voltage readings first on all four coils, this will tell you if your amp is switching correctly

the triggers at .5v ?? where is that electronics degree coming in??

this is your bias voltage to forward bias those transistors in the amp to switch the 150vac to the coils thus if you are getting the 150vac to your coils no need to do the trigger voltage check as it is working confirmed by the output voltage to the coils if you are not getting 150vac to your coils then look at the trigger voltage,

I think you got your ignition problem licked as it is going to be bad coils, the two epoxy repaired ones, after you confirm the 150vac to the coil then do a spark check using a spark tester purchased from auto parts store, set the spark gap to 7/16" and see if you get a nice blue spark, make sure you file off the paint on the end of the adjustment screw so there is a good path to ground for the spark to jump, this will confirm the weak coils, should be around 30k volts on the output of the coil basicaly a 200 times step up transformer, if you have a high voltage probe attachment that reads that high you could use it,, spark tester is better though, and less expensive than a high voltage probe

 

[Randyg123]

Re: 1973 Johnson 85HP Cylinder Order

the coils

you can go from one orange lead to ground with the probes, ac voltage, the one going to the coil on the orange wire put red meter, the black to ground
of course you will only be reading the positive protion of the ac sine wave but it will work should give you around 280 dc or higher

I would do the coil voltage readings first on all four coils, this will tell you if your amp is switching correctly

the triggers at .5v ?? where is that electronics degree coming in??

this is your bias voltage to forward bias those transistors in the amp to switch the 150vac to the coils thus if you are getting the 150vac to your coils no need to do the trigger voltage check as it is working confirmed by the output voltage to the coils if you are not getting 150vac to your coils then look at the trigger voltage,

I did a quick check of the coil voltage this AM before I ran off to work. I had about five minutes! Got my son to turn the key as I held my DVA probes across the corresponding points on the powerpack. It looked like I was only getting about 230-235 volts this time but the signal was much noisier than before. I don't think I was getting great contact with my probes at the time. When I did the first readings, I actually tightened my probes under the each screw on the powerpack so I could crank the starter (i only got two hands). Doing so gave me good contact and a stable signal. [BTW - After each crank, it took about 10-15 seconds for the cap to discharge. Is this similar to what you experience with your homemade DVA?] Anyways, each coil gave the same voltage. But is this too low?

I've already ordered some coils and they should arrive tomorrow. Grabbed four of them as I suspect the two ports are toast due to the cracks and one starboard has a puddle of thick goo under it (like the old PCB stuff you used to see all over the place ).