Johnson 4Hp J4BRECJ.98

Bushman II · Feb 24, 2004

Johnson 4Hp ModNo J4BRECJ.98, SerNo 09399120 1/97 Since 1997 my Johnson 4Hp has been working like a Rolex, now deep deception: it is just dead! No firing no sparks ! I bought a new CDI, took 2 1/2month to get it here Mounted everything: no sparks Verified all cables and connections: no sparks Took it to the dealer in Penang/My <onomichi@hotmail.com>, he tried all again: -all cableconnections -->ok -ignition coil reading primary 0,01 Ohm, secondary 0,30 KOhm (acc to manual

k)-->ok -sensor coil reading 112 Ohm (acc to manual

k) - all ground contacts -->ok -with the new CDI: NO SPARKS -with the old CDI: NO SPARKS -with another working ignition coil: NO SPARKS -We took the flywheel off, nothing wrong, the magnets are strong. Can anyone help what to do further????

rickdb1boat · Feb 24, 2004

Re: Johnson 4Hp J4BRECJ.98

Kill Switch problem, if it has one????

cobra 3.0 · Feb 24, 2004

Re: Johnson 4Hp J4BRECJ.98

Have the spark plugs and cables been changed? They could be faulty... ...when did this motor start giving you grief? Before or after the CDI change?...after a spark plug change? Did you transport it or drop the motor? I am trying to determine exactly when it stopped working.

cobra 3.0 · Feb 26, 2004

Re: Johnson 4Hp J4BRECJ.98

Hey Georg, did you ever get this thing going again?

Bushman II · Mar 1, 2004

Re: Johnson 4Hp J4BRECJ.98

-Killswich disabled -Have still the old plugs working, but even with new plugs and cables: NO sparks - Motor still on the transom, just did not start again the next day, no sparks - sombody knows if/what could be wrong with the magnets in the flywheel? The suggestion sounds incomprehensible to me, but someone might know better?

Bushman II · Mar 9, 2004

Re: Johnson 4Hp J4BRECJ.98

The thing is not yet running. Johnson under Bombardier gives no E-mail where to ask for assistance. Does anybody know if and what could be wrong whith the flywheel magnets??? They seem to be strong, at least they attract a spanner with sharp clack, what else could be??

Xcusme · Mar 9, 2004

Re: Johnson 4Hp J4BRECJ.98

Georg, You didn't mention the reading you should have taken from the Charge Coil (under the flywheel). This coil produces the voltage to charge the CDI powerpack. Without this voltage, you won't have any spark. The sensor coil you do mention, triggers the flow of current to the primary side of the coils. A service manual details the tests to run to determine which part(s) are defective. Shotgun replacement of suspected parts can get costly. Take the reading and know for sure.

OBJ · Mar 9, 2004

Re: Johnson 4Hp J4BRECJ.98

X is right on the money Georg....there is a systematic approach to tracking down the bad component. The service manual does this. Your dealer should have the service manual and should follow it. Follow Xcuseme's advice and check the Charge Coil output and Sensor Coil.

Bushman II · Mar 11, 2004

Re: Johnson 4Hp J4BRECJ.98

Thanks for the advise Xcuseme, But, sorry, on this engine there is no such coil accessible under the flywheel. - There is the flywheel with the cast in magnets - The CDI - The sensor, about opposite of the mounted CDI - The Ignition coil which is said to be the same on all Johnson up to 30Hp(?) The Johnson/Mercury/etc dealer/mechanic here is baffled himself by the thing. We are trying to get as well assistance from Bombardier Singapore, we just gave them the following: From: Georg Rehnert Bushman II and Geron Ngo at Onomichi Marine Re: Johnson 4Hp 12/03/04 Dear John, I am just recapitulating here what we have as open questions: 1) Engine data: Johnson 4Hp, two cylinder Model No J4BRECJ.98, Serial No 09399120 1/97 2) Resistance readings : 2.1)Ignition coil, you said: primary (ohms) 0.1 +/- 0.05 We measured: primary 1 Ohm 2.2)Ignition coil, you said: secondary (ohms) 275 +/- 50 We measured: secondary 290 Ohm 2.3)Sensor Coil, you said

ohms) 100 +/- 15 We measured 112 Ohm 3) Spark Plug you said: QL86C or L86C (gap at 0.030 in. or 0.8 mm) We still use the original plugs Champion QL86C, nicely cleaned and set, but even with NGK's and leads from another engine: no sparks 4) Ground contacts on CDI and Ignition coil >ok (are there others to check?) 5) Kill switch disabled 6) CDI Part No 584243, I have a NEW one mounted, still no sparks. 7) Ignition coil Part No 583740, said to be the same as for other Johnson engines, so we took one from another engine, still no sparks. 8) Flywheel Part No 583840, a used one is not available here for testing, but both magnets seem to be ok, they snap a spanner with a sharp clack. Again, what could be wrong with the magnets??? Kind regards Georg

Xcusme · Mar 12, 2004

Re: Johnson 4Hp J4BRECJ.98

Georg, How did you 'disable' the kill switch??? It looks like you have a monolithic coil assembly (2 coils in one pack) , right?? Your resistance readings on the coil primary(1 Ohm) is 10 times the normal spec of .1...is this for both coils?? BTW, if your magnets are strong enough to attract a spanner or screwdriver with a sharp 'clack' they should be good. Magnets don't just go suddenly bad. Did you do a resistance test of both "sensor" wires to ground?? You said the coil itself had 112 Ohms. I think what you'll find is that you have an under flywheel ignition system, the CDI is mounted under the flywheel. The sensor would be built into the CDI module itself. The other 'coil' under the flywheel is the charge coil. Positioning the CDI module and the charge coil in relation to the flywheel (spacing air gap) is important. If there's too much of a gap for either, you might loose either the charge voltage to the pack or loose the sensor signal to fire the CDI. Either way, a no spark condition would result. These are just guesses as I don't have a print of your motor and I can't find that Model Number either. Good Luck and post back if you get this sorted out, others can benefit for your findings.

Bushman II · Mar 14, 2004

Re: Johnson 4Hp J4BRECJ.98

Hello Xcusme, It seems that this (assembled in China)model has been only on the Asean market. In My as well it is not well known. OK, closer description of the 2Cylinder Ignition: -there is the flywheel with the two cast-in magnets one opposite the other and each one has two "faces" appearing flush at the rim of the flywheel. Nothing is mounted to it which could be taken off or could be adjustable -the CDI is mounted on the let's call it the frontside, positioned with a spacing of about 0,5 mm, the thickness of a piece of light carton, the two magnet 'faces' are attracting it strongly and evenly. I thought first this will be the cause, because the outer steel lamelles on the longer feeler had somewhat separated, opened by rost. So I have bought a new one, first repair after five years. -the Sensor is mounted opposite side, so on the rearside of the engine, above the cylinders, on a plate, so it is adjustable in position versus the CDI, in order to adjust the timing. -the Ignition coil is mounted on the Stb side close to the cylinders. Two contacts IN from the CDI, two leads OUT to the spark plugs. As I said, the Ignition coil is said to be the same part on all Johnson's two cylinders, up to 30 or 40Hp. So we tried with another coil from a working engine, no sparks. -the killswitch is disabled by pulling it's two wires from the plug at the CDI, so there are only four wires left in the plug, two from the Sensor and two to the Ignition coil. I shall go to the shop again and measure the resistances on each wire against ground again. Georg, still

Xcusme · Mar 15, 2004

Re: Johnson 4Hp J4BRECJ.98

OK, now we are getting somewhere. As an aside, this is a classic example where a service manual would make short work out of diagnosing your problem. You listed resistance figures et al , you didn't mention if you or your 'tech' had access to a service manual either. You mentioned that the CDI module itself has 'steel laminations' that had some rust. These laminations would imply that the CDI itself has the charge coil imbedded and the other 'sensor' is the trigger coil for the CDI. Typical trigger coil or sensor coil resistances are in the range of 40 Ohms , not 100 +/- 15 ohms, but your coil could be different. I'll try to explain how a typical CDI ignition works and then you can apply these concepts to what you have. Under the flywheel you would have 2 coils, one is a 'charge coil' , this produces voltage to the CDI pack, which might be mounted on the side of the powerhead. The other coil is smaller, usually enclosed in a plastic enclosure and is the 'sensor' coil. It's function is to 'fire' the CDI. The CDI module has a separate 'ground' lead that has to be connected under a mounting bolt, making good connection to the powerhead. The voltage output of the CDI module (approx. 200+ volts) leaves the CDI module thru this 'ground' wire and makes contact with the powerhead. They are using the powerhead itself as a common conductor to supply voltage to the base of the coils. The voltage then enters the coils thru their ground connections. This is actually the primary side of the coils. A small wire leaving the coils (still the primary side) then goes thru the plug in connector , back to the CDI module. The CDI module will then complete the circuit and fire that cylinder when it gets a signal from the SENSOR COIL. Both cylinders will be fired by the CDI module, first one than the other, alternating, based on the signal sensor coil. In your case, things are basically the same, only the parts are mounted differently. The CDI module has the charge coil built in and mounted under the flywheel, it should be charged by the spinning flywheel. The other coil is the sensor coil and it fires the CDI module. It's interesting to note that you say that the sensor coil is adjustable for timing. Usually the timing of the motor is a function of the position of the flywheel on the crankshaft. This position is determined by the flywheel 'key'. If this key is sheared off, it allows the flywheel to move out of position and your timing will be off. It won't stop the spark, it just won't fire the cylinder at the right time. Ignition timing is either advanced or retarded when the throttle linkage moves the armature plate. Both the CDI module and the sensor coil should be adjusted so that they are as close to the flywheel as possible , but not touching the flywheel. If the CDI coil laminations are too far away, it won't produce and charge voltage. If the sensor coil is too far away, it won't fire the CDI pack. There are 3 things at work here. 1. The sensor coil could be bad, either too high a resistance, or improper gap to the flywheel. If you were to measure the voltage output from the 2 wires leaving the sensor , you should see a very small voltage, when you crank the motor. No voltage, no trigger to the CDI, no spark. 2. Bad CDI, if the CDI charge coil is defective, or it's air gap too wide, again no primary voltage created, no spark. 3. Bad coil pack. Either internally shorted on either side or open coil windings. All 'ground' connections have to be good and have a star washer to effect metal to metal contact. Either the CDI is grounded itself or has a flying lead that is grounded to a mounting bolt. The coils should be grounded thru it mounting base. All of this is guesswork as you might have figured out , as I don't have a circuit print of your motor.

Bushman II · Mar 15, 2004

Re: Johnson 4Hp J4BRECJ.98

Hello Xcusme, Here at first I have measured again all the resistance's: A ) CDI to Ignition Coil Primary, measured in kOhm against Ground on the end of the cables to the Coil: CDI old: Cyl 1: none, Cyl 2: none, in-between the two cables: none A.a ) CDI new: Cyl 1: none, Cyl 2: none, in-between the two cables: none B ) CDI to Sensor measured in kOhm against Ground on the pins in the plug of the CDI: Pin for bl/w cable:none, Pin for wh/bl cable:none Inbetween the pins: none C ) Sensor, measured in kOhm against Ground on the end of the cables to the CDI: Bl/w cable: none, wh/bl cable: none, in-between the two cables: 0,111 kOhm D ) Ignition Coil, mounted on the engine Primary against Ground: Cyl 1: 0,001kOhm, Cyl 2: 0,001kOhm, in-between the posts: 0,001kOhm D.d ) Ignition Coil, mounted on the engine, Secondary against Ground: Cyl 1: 0,295 kOhm, Cyl 2: 0,296 kOhm, in-between the posts: 0,591kOhm E ) For comparison I have measured two other Coils in same mounted position: The readings differ only 0,004-0,005kOhm F ) Both cables to the spark plugs: 0,001kOhm G ) The probes of the Ohm meter connected: 0,001kOhm or 1,1Ohm, that for the precision of my instrument. My 'tech' has Johnson manuals, but not the one exactly for this engine (not commom here). However, for the similar engines the data are similar and the measured resistances fit fine. I checked the strength of the flywheel magnets again: both the same: clack. How can the necessary strength of the magnets be defined? Now to your fine explanations. I have to study it in detail, but your "The CDI has a seperate ground" already has lit a light! We disabeled the killswitch by taking the wires out of the plug at the CDI. There were not two wires only, but three! And one of them is a groundwire married to the one from the switch and the other end to the block! That is maybe the 'seperate ground' to the CDI you mentioned. I shall check that, be back soon!

Xcusme · Mar 15, 2004

Re: Johnson 4Hp J4BRECJ.98

Thanks for the update. Know this about the kill switch and it's 2 wires. One wire should goto the powerhead 'ground' connection. The other wire from the switch goes to the connector back into the CDI module. When you push the kill button, you short out, (kill), the internal charge capacitor inside of the CDI module. This kills all output voltage, and the motor stops. Internally the kill switch is 'open', there's no connection of the 2 wires until you press the kill button. The 'ground' wire connection, on the power head is not really a ground connection, it's voltage will show (on a running motor) about 200+ VDC. As I said further up the thread, the powerhead is used as a current carrying conductor. This is how the output of the CDI module sends its constant output voltage over to the coil pack, thru the power head itself. This is why I said to check to see if the CDI is grounded with either a mounting bolt or by a flying lead to the powerhead. Since the coil pack is connected to the powerhead (bolted), the coils get their primary voltage. The 2 smaller wires leaving the coils, go back into the CDI module and are then alternatingly grounded thru the CDI to complete the circuit, and fire the cylinders,first one, then the other. BTW, you should disconnect the wires of the sensor coil from the CDI module and then take your reading. Having the wires connected to the CDI will give you erroneous readings. To disable the kill switch, just remove the wire going from the switch to the power head and insulate it from touching anything. Be sure that neither of the 2 kill switch wires are touching any metal and that the insulation on both wires is good.

Bushman II · Mar 16, 2004

Re: Johnson 4Hp J4BRECJ.98

Here some more: I fact it is the kill-switch itself which has 3 wires: 1) one bl/ye to the CDI plug 2) one bl to the CDI plug and 3) one bl to the block, say ground. The No 2 and 3 are apparently connected inside the switch, continuity is there. So there is a permanent ground wire to the CDI We found in a manual 'to disable the swich, just pull the No 1 wire from the plug' so the bl No 2 should remain (to provide the ground, I suppose). The Sensor had been measured while disconnected from the CDI

Xcusme · Mar 17, 2004

Re: Johnson 4Hp J4BRECJ.98

OK, Grab your meter. Set meter to DC volts, autorange if it has it... Place the RED test lead on the powerhead Place the BLACK test lead in the hole in the CDI plug connetor where #1 wire was originally. Pull starter rope You should read the output of the CDI module (approx 180-220VDC)

Bushman II · Mar 22, 2004

Re: Johnson 4Hp J4BRECJ.98

Hi Xcuseme, OK, all hassle over, the bug is running again! Thanks for the tip with the seperate ground for the CDI. That lit me the light! It is the third wire into the stop switch, it is there connected with the black wire to the CDI. Not a particularly intelligent and clever routing for the ground, the mecano said it's as well new to him. We put this back and the thing is working again. Knowledge is all!! Finally it was only the stop switch which was faulty. The CDI I bought is useless now, you want to by it? Regards

Georg

Xcusme · Mar 22, 2004

Re: Johnson 4Hp J4BRECJ.98

Well Hello!!! Gees, I thought you got abducted by aliens or something!

Yup, it's the simple things sometimes that can really drive you up the wall. I'm surely pleased you got the problem sorted out. Sadly , I don't need your old CDI module, it might not be a bad idea to keep it around for a spare. You hear a lot of talk, here on iboats, from some very experienced folks (far more knowledgeable than myself to be sure) that a service manual and wiring print are 'must have' items. I guess a little common sense thrown in couldn't hurt either. Again, I'm glad you fixed your problem. Thanks too, for reporting back with your findings. Others can, and will, benefit from your experiences. Best wishes, Xcusme

Johnson 4Hp J4BRECJ.98

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