40hp Johnson not firing

I have a 1973 40hp Johnson which I cannot get to fire. I have replaced;
Coils/laminations.
Condensers.
Points.
Plugs.
Any ideas?

Much obliged.
skipper47

Did you torque the flywheel to 105 ft lbs? disconnect the two small black wires coming from the points plate and isolate them and then see if she fires?

Agree with the above. New points from the factory do have a film on them.

I have run into this before....make sure the magneto plate is grounded to block with jumper wire

Use acetone or laquer thinner to clean the points and feeler guage. Do not sand or file new points it greatly reduces service life of the points. Use only BRP name brand points and condensers aftermarket parts are crap.

It is a pain in the but but the best way to adjust the points is with a timing light. Start out with exactly .020, torque the flywheel down and shine the timing light at the two marks on the outer edge of the points plate. The single mark on the flywheel needs to be inbetween the two marks on the plate. Ignition timing is fixed with point gap and without the timing tool the timing light is the most accurate. You engine will purr like a kitten once timed properly.
Another common fault is not torqueing the flywheel nut to 105 ft lbs. If the flywheel key has a little crease the engine will not run or run properly.

kimcrwbr1 said:

It is a pain in the but but the best way to adjust the points is with a timing light. Start out with exactly .020, torque the flywheel down and shine the timing light at the two marks on the outer edge of the points plate. The single mark on the flywheel needs to be inbetween the two marks on the plate. Ignition timing is fixed with point gap and without the timing tool the timing light is the most accurate. You engine will purr like a kitten once timed properly.
Another common fault is not torqueing the flywheel nut to 105 ft lbs. If the flywheel key has a little crease the engine will not run or run properly.

Click to expand...

Excellent advice from all, will get on to it.

Many thanks,

skipper47

Coil placement is very important as well as if there is any wobble up and down on the plate you need to replace the ring and bracket. Did you pull the plate when replacing the coils if not you need to go back and install the coils properly. Pull the plate and take pics then pull the coils and then push the wires fully into the coils and then slide the boot up tight then reinstall the coils. Take note of the #1 spark plug wire is marked with a metal band, make sure that wire goes to the #1 coil.

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(Magneto & Driver Coil Alignment)
(J. Reeves)

To align the coils properly, have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit. This creates the proper distance between the coils and the flywheel magnets. Faulty alignment creates friction and the yokes of the coils heat up, turn blue and expand.
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(Point Setting Of Magneto Models)
(J. Reeves)

Note that there are other ways to set points such as using a ohm meter or timing light... however, the following will result in a setting so close to being exact that one could not tell the difference.

Make sure that your feeler gauge is absolutely clean so as NOT to transfer oil/grease to the points.

Set the points as follows. Have the flywheel key aligned with the fiber rubbing portion of the ignition points. Adjust the gap so that a .020 gauge will pass thru but a .022 will not. Should there be any question of the points being dirty (touching the contact with your finger would cause them to be dirty), clean them with a small brush and acetone or lacquer thinner.

NOTE 1: Should the operating cam have a small portion on it with the word "SET" imprinted, align this portion with the fiber rubbing portion instead of the flywheel key.

NOTE 2: Should the cam have the word TOP embossed on the top of it, that is a cam that could be installed upside down and this is simply telling you which side is up. It is not a position where one would set the points.
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(Regular Magneto Coils - Continuity Test)
(J. Reeves)

Checking the continuity of the ignition coils....... Have the ohm meter set to High Ohms.


Remove the primary wire from points. Remove the coil ground wire. You do not want either of these wires touching anything.
Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground wire of the coil.


Then touch (still with the red lead) the primary wire. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire.


If there is no continuity between the secondary circuit (spark plug) wire and the primary or ground, remove the coil from the armature plate, then check the continuity directly between the prong within the coil (prong that the plug wire connects to) and the primary and ground. Poor or no continuity of a coil (or plug wire) is one reason for weak spark, s/plug fouling, or no spark.
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(Magneto Coils Failing/Burning)
(J. Reeves)

The only reasons coils on a magneto ignition system would burn up every so often is that somehow there is a low amount of battery voltage being applied to them, or they are not aligned properly.


Whatever accessories that may be used, do not run their ground wire to the black wire or black/yellow wire ("M" Terminals) on the ignition switch, push button switch, whatever as those black wire leads to the primary circuit of the ignition coil(s).


Voltage TO any accessory also contains voltage FROM the accessory in its ground wire to complete the circuit. Have a fuse panel set up, or run those accessory ground wires directly to the negative terminal of the battery to keep those voltages away from the magneto system.

If no accessories exist but a ignition switch is being used, the switch may be faulty and allowing a small amount of voltage to travel from either the "B" or "A" terminal of the switch to one of the "M" terminals. That can be checked with a volt meter set to the lowest voltage setting.


If there are no accessories and no ignition switch, I'd suspect that the coils out of alignment. Have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit, creating the proper distance between the coils and the flywheel magnets. Faulty alignment creates friction and the yokes of the coils heat up, turn blue usually, and expand.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************
(Magneto & Driver Coil Alignment)
(J. Reeves)

To align the coils properly, have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit. This creates the proper distance between the coils and the flywheel magnets. Faulty alignment creates friction and the yokes of the coils heat up, turn blue and expand.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************

To answer some of the questions, yes the flywheel was torqued to 105 lbs and yes I mean no spark.

I am going to spend some time this week end to go over all the excellent advice, and yes I will take photos.

My experience in outboard motors as you can see is limited, my experience is in stand-by diesel generators, many thanks for the many posts.

skipper47

Guys, went to the boat to do the work you all advised me on, when I took the flywheel off, one of the coil laminations had been damaged, some of the layers had parted and the top one buckled.
Done all the other, cleaned points and reset, there was grease on the flywheel key, cleaned off.
I have another question, the unit is 40RL73D, can anyone tell me what the "D" signifies please?

skipper47

That is a mafucturer designation and only means something if noted on the individual parts in the diagram. All 40hp jonnyrudes in 1973 had the D designation.

I forgot to ask, I am moving my office at home and mislaid my manual, can someone post a diagram of the powerhead for me please, so that I understand what you are all referring to?

skipper47

Just click on evinrude parts and pull up the parts diagrams.

Thanks kimcrwbr1.

kimcrwbr1, got the parts diagrams, thanks.

It reminded me about something else that may be affecting my starting problems and that is, the cut-out switch.
There is a wire going from the cut-out switch up to a micro switch that seems to run on the shaft for the flywheel, but then there is no wire on the other side of the micro switch, is that correct?

Thanks.
skipper47

joereeves, thanks.

skipper47

What a dumbo, some of my previous statements were incorrect, progress so far.

Points are now as accurate as I can get them, the flywheel was not torqued as previously stated. The oiler felt had come off its position stopping the coils being set on the two butments as told.

I am now waiting for my son-in-law to come and give me a hand to torque the flywheel, finding it difficult to hold the flywheel and torque the nut on my own. Keep you all posted.

skipper47

Flywheel holder tool, found in any auto parts store. Actually used by auto mechanics to turn the flywheel when installing a manual shift clutch pressure plate. The curved section usually needs heating and a slight addition to the bend to grab the flywheel teeth of various horsepower models.

Could be a free loaner tool at auto parts store

Thanks Guys, good one.

I suppose a suitably sized "C" spanner with a tube extension would do the job? Although thinking about it there be only one to grip the teeth and not two, is that advisable?

skipper47