Johnson no spark

[old yeller]

I have a 1972,Johnson 125 H.P. outboard with no spark to the plugs.Is it possible for a bad rectifier to cause this problem?I have a Clymer shop manual and have performed tests on all systems.The following are the results of these tests.The rectifier is no good. The sensor tested ok. the pulse pack input is ok, plus its brand new. the pulse pack output is no good. the coil is brand new, but of course its not getting anything from the pulse pack. the clipper circut tests no good. what im asking is the system appears to run on direct current, with the rectifier changing alternating current to direct current. Is it possible that the pulse pack is receiving only alternating current and it sences that the ignition system is off? any help would be greately appreciated as I'm confused.I'm about to pull the little remaining hair that I have left out. Thanks in advance for the help

 

[clanton]

Re: Johnson no spark

If you got the pack and coil from Rapair, they used to recommend removing the clipper. I would replace the rectifier or disconnect the red wire from rectifier to battery. Just use a hot battery for testing.

 

[old yeller]

Re: Johnson no spark

Clanton,thanks for the quick reply.I got my pack and coil from Napa Marine.The directions did not indicate removing the clipper.<br />I removed the rectifier and bench tested it.How would I test with a "hot battery"? The battery in the boat is brand new and fully charged.

 

[emmerson2]

Re: Johnson no spark

old yeller <br /> <br />Has your engine got a deadman switch. If so check that it is not opporative.

 

[clanton]

Re: Johnson no spark

Disconnect the 2 yellow wires from stator tape the ends and insure they dont get caught in flywheel. This elemnates the charging system, then the only power you have is battery power. The pulse pack is battery powered, and needs at least 9 1/2 volts to work, The pack may have been rebuildt by Rapair and sold by NAPA, Rapair has a tech service phone try 256 772 3829

 

[old yeller]

Re: Johnson no spark

again, thanks for your reply. i disconnected both yellow wires from the stator and with a fully charged battery attempted to start this wonderful johnson motor that i have. I still have no spark to all 4 plugs. I then called napa marine tech support at 1-217-324-9475. I explained to him what i had done up to this point and believe it or not he said im doing it right!!!!!!!!! He stated that he would start with the rectifer frist, as you need direct current to enable the pulse pack to put out the 250 volts to the coil in order to fire the plugs. Well, i guess ill go spend another 40.00 bucks to maybe get this piece of junk thats all mine running, unless of course you can think of something else to prove his theory correct or incorrect. Again, thanks for the help. if you ever need help with a ford automobile (1960-1985) give me a holler, ill be glad to assist

 

[clanton]

Re: Johnson no spark

If the engine is as you say and has a pulse pack, the pack is powered by 12 volts DC supplied by purple wire fron ignition switch, the switch is fed 12 volts DC from starter solenoid by a fused red wire. The only thing the AC coil does is charge the battery thru the rectifier, which has 2 yellow wires, 1 with gray stripe. The pulse pack should have 1 purple wire, 1 blue wire, and 2 wires from sensor, does not show color. Rapair your best bet.<br /><br />If Schemaic looks at this post he may be able to email you a diagram of the wires.<br /><br /> If you have at least 9 1/2 volts input to pack at cranking rpm , the sensor, rotor, cap, and wires are good, the pulse pack should have output of about 250 volts on blue wire to coil, if not the pulse pack is bad.<br /><br />Have you checked the anti-reverse spring, and sensor air gap?<br /><br />You can check the input and output voltage at the termial board on the engine, number 5 should be blue, number 9 purple, the 2 sensor wires go direct to pluse pack.

 

[old yeller]

Re: Johnson no spark

I just went out in my yard and pulled off the flywheel again. checked all wires up top with a ohm meter again- all check out ok. checked the anti-reverse spring its in place and after i put the flywheel back on, i checked if it works and its ok. The distributor cap and rotor appear to be ok- no craks or carbon tracks.No rust, dirt, or any type of debris under the flywheel. I set the gap at .028 and put it back together. The pulse pack is wired as follows: two black and white wires from sensor to pulse pack----blue from pulse pack to #5 on the terminal block----purple wire from pulse pack to #9 on terminal block-----black with green from pulse pack to sensor---I wired this right from the directions that came with the pack. The voltage at cranking is above 11 volts. I was using a remote starter with the key on when I was cranking it and trying to read the ohm meter at the same time so voltage is approximate, it gets a little hairy doing 50 things at once, but im sure I have above 9.5 volts.. Well it looks like another pulse pack. How the heck can a new pulse pack go bad? When i put the new pack in I tried to start the motor once with the muffs on and it fired right up! Of course it hasent run since. Im going to name this boat Christine. Thank you very much for the assist.

 

[ajp]

Re: Johnson no spark

I would find an "actual factory service manual" and go through the trouble shooting lists before I bought another powerpack. I thought my pack was bad till I went through step by step. My problem turned out to be a faulty wire to the air gap sensor. Fixed that and wow, loads of blue spark. Then the next time out it started cutting out and then would not start. Pulled the flywheel and reset the gap at .028 and runs great again. Get a real manual.<br /><br />Arlan

 

[clanton]

Re: Johnson no spark

Is easy enough to check the sensor wires, disconnect at sensor and pack connect meter wiggle wires.

 

[old yeller]

Re: Johnson no spark

When I pulled the flywheel off a few hours ago, I put one from my ohm meter on one side of the sensor and the other wire on the other side of the sensor. Was that ok? It read infinity. I assumed that was ok.

 

[old yeller]

Re: Johnson no spark

I just got off the phone with napa marine tech support. They walked me through the test proceedure, to which I had already completed. They then took my name and adress and are sending me a new pulse pack as they said it is the only thing they could come up with that is no good. At this time I asked them how a brand New pulse pack could go bad and they replied that it was probably no good to start off with, and that they stand behind there parts even though there are no returns on electrical parts. Boy am I happy. All I could think about is spending another 300.00 bucks. I want to thank you-all for your help, especially Clanton, who replied to my sos almost immediately. Again thanks and when I get the new pulse pack, ill let you-all know how it turned out

 

[dpminc]

Re: Johnson no spark

You should not have infinite resistance across the trigger sensor. This should be low (6-13ohm) They are fairly common to go bad, and are also expensive, but available used at www.twincityoutboard.com. I do not know why sierra (napa) would have directed you to the rectifier?!? a failed diode in the rec. can cause funny misses and such, when running because of stray AC current disturbing the trigger circut in the pack, but would not cause a no spark condition. As shown above, you MUST have >9.5 (10 is better) volts CRANKING, or the pack may not fire, and the transformer circut in the pack may be damaged.

 

[ledgefinder]

Re: Johnson no spark

What gap are you setting to 0.028? You should have a sensor on your timer base (125hp), but it's possible that a set of points has been substituted in there (they ran points on the less-expensive V4s, 1969-72). If the airgap between your sensor coils and the flywheel is 0.028", that'd explain your problem right there. The gap should be much less than that (don't remember the number right off, but it's just about touching). However, something's wierd here, because one can't set the sensor airgap without having a special tool that mimics the OD of the central section of the flywheel. <br /><br />The pulsepacks are different for sensor versus points systems.

 

[ajp]

Re: Johnson no spark

The gap on my 1969 115hp v4 is .028 per the factory service manual. I would also probably bet that his power pack is fine. <br /><br />PS If anybody needs a powerpack, go to Seiler Marine on the web. $100 bucks cheaper than NAPA and $200 less than a boat dealership. I got a powerpack for $225 for my 69.