1977 Johnson 140 No Spark

[HOUSTON1]

All,<br />I have a Johnson 140 that will not start. The last time it ran (about 2 weeks ago), I was running across the bay and ran across another boats wake and the motor died out. I was subsequently able to start the motor (reved way up) but it was missing and I couldn't put it in gear or it would die. I got towed back to the ramp. I since replaced the fuel, filters, pulled the plugs and turned over, and cleaned carbs. I thought maybe I had some water in the fuel system. I now cannot get it to start. I looked through my owners manual and looked at the checklist. After checking each plug I relalized I was not getting any spark on any plugs. I checked the key switch and it appears to be working fine. I notice when checking for continuity at the black/yellow wire (kill wire?) on the power pack (btm right terminal) that when cranking it shows ground (it also shows ground when key is off). I disconeccted that black/yellow wire from power pack to see if I could keep the power pack from getting grounded when cranking (trying to isolate problem) and when I cranked it it stil showed ground at that terminal. It appears to me in the diagrams that if that wire shows ground to the power pack that it won't let the powerpack energize. I am trying to follow the manuals checklist, but I don't have a neon light tool and some of the other type tools reffered to in the book and it doesn't really make alot of sense anyways.. Hoping someone may be able to give me some things to look for and common instructions on how to do it. I am puzzled how my motor can run fine all season, then all the sudden I don't have spark and it wont start. Any help or ideas on what it could be would be greatly appreciated. I don't want to have to find a fix by swapping out parts..

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

I left a few things out. I do have a snap-on digital miltimeter, but did not understand the manual directions for testing the stator/coils for ohm loads? The motor has between 125-120 psi compression on all cyl. I suspect the problem may be with the powerpack, because with the black/yellow wire disconnected the terminal on the powerpack shows ground when cranking. Sorry for lengthy explanation just wanted to make sure I convey as clearly as possible what I am looking at. I am pretty good with big motors, but am still trying to learn outboards. Thanks again for any comments/suggestions.<br /><br />Regards,<br />Shane

 

[andy6374]

Re: 1977 Johnson 140 No Spark

First off, you should probably post a model number to give people some reference. Does it have a single powerpack or two. You should get yourself a service (not owners) manual if you continue to plan on working on your motor.<br /><br />I don't know the numbers you are looking for, the ohms between stator ouputs and peak voltages (which you need a DVA, anyways), but for staters make sure there is continunity between the high speed and low speed stator coils. If this doesn't check out you won't even need to worry about the resistence between the the leads cause the stator is shot. Check for continunity between the yellow and yellow/gry as well, this is for charging but if this shorted you will have to replace the stator anyways.<br /><br />As I know far more about merc's than OMC, I will shut my mouth for now and wait for some of the pro's to answer.<br /><br />-andy

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

Andy,<br />Thank you for the repsonse. I incorrectly stated owners manual, it is indeed a service manual (bought through this site). Since the boat is not kept here, unfortunately I will not be able to get the model number till midweek. It is a 1977 Johnson V4 140 with a single power pack located on the back between the heads. I am hoping that the model number would not be critical to diagnose a problem. I will check the yellow and yellow/gry as you suggested. I am not familiar with acronyms (DVA?). Are you referring to a dilgital voltmeter? If so, good, I have one. Thanks again for any help.

 

[MCM]

Re: 1977 Johnson 140 No Spark

Hi Shane, Have you checked all elec. connections to make sure they are clean, free of corrosion and tight? maybe there's an off chance something was jarred loose by hitting the wake. Try disconecting the large red plug on the engine harness and test for spark by jumping at the starter solenoid, if the spark returns then the problem may be in the ign. switch or harness, keep in mind that if the motor starts w/the harness plug disconnected you won't be able to shut off without choking it off or removing the fuel supply which is why I disconnect the fuel line from the motor beforehand.

 

[DHPMARINE]

Re: 1977 Johnson 140 No Spark

I only see three models listed for 1977 140 HP engines.Manual tilt long,power trim long and extra long.No difference in the ignition systems.<br /><br />Did the rpms go 'way up' when you hit the wake or when you restarted ?<br /><br />Either way I would look at the flywheel key before going much further.Then forget that neon tester and look into Stevens Instruments CD-77.It is a peak reading volt meter,and the instructions are greatly improved over the 1977 manual and that neon tester.<br /><br />DHP

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

MCM & DHP,<br />Thank you both for the responses. I have checked all connections and nothing is loose that I can find. That was my initial thought as well. Disconnecting the harness is a good easy idea, and I will try that next. DHP, I have T/T and beleive my model number is the TL, but as you stated I figured the ignition was the same on all. The rpms did not go way up, just sputtered out and died. Immediatly after it died I was able to get it started, but only with the throttle very advanced. As soon as I brought the throttle down to put it in gear it would die. Once I got it home, I was not able to start it again. I will check the flywheel key. I am afraid this may have something to do with the stator, timing base, or power pack. Unfortunately I know very little about these items. I will go through the service manual and do whatever I can before taking it in to a mechanic. Being a do-it-myselfer though I sure hate to do it. Any other idea's are welcome, I will be going down this weekend to work on it, and will print this thread before going. Thanks again for all the feedback thus far!

 

[MCM]

Re: 1977 Johnson 140 No Spark

Shane, As you seem to be familiar with doing your own work these links will give you the expected peak DVA and ohm readings for your motor as well as instructions and some good troubleshooting info.<br /><br /> http://outboardparts.com/omc/troubleshooting/troubleshooting5.htm <br /> http://outboardparts.com/omc/troubleshooting/trublshtinghlp.htm <br /><br />Hope they help and keep us posted

 

[Seasport]

Re: 1977 Johnson 140 No Spark

Also check out the following site for an ignition system troubleshooting guide (a lot of this is reprinted from the Rapair troubleshooting guide which can be downloaded from www.rapair.com)<br /><br /> http://www.boatpartstore.com/tips.asp <br /><br />I'm not sure that you can read much into the fact that you are measuring a ground connection at the black/yellow powerpack output during cranking. You are measuring the output of an active electronic circuit with an ohmmeter. Not a meaningful test. From what I recall, when this terminal is grounded it dumps the charge out of the internal powerpack capacitor through a resistor (and hence kills the ignition).<br /><br />Could well be a faulty powerpack though. You need to work through the various voltage & resistance tests to isolate the problem.

 

[gatorred]

Re: 1977 Johnson 140 No Spark

try kill switch or control bax with safty switch so it's thinks it in gear so it kill spark rule out odd stuff

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

All,<br />Thanks for the continued support. MCM very helpful links. Seasport, You are probably right about the continuity test I performed. I just found it odd that with the key in the off position the blk/yel wire was grounded, while cranking that same wire was grounded, and with the blk/yel wire removed the terminal was grounded. I will definetly have to do my homework though and make sure the troubleshooting tests I do are logical in nature and not just poking around. Gator, I have pretty much isolated the switch and controls, but will retest everything per the recommendations of this thread. The motor wouldn't crank if it were in gear though. Thanks for all the help I am really anxouis now to get down there and fix this problem. Any other useful tests I should try give me a shout. <br />Much thx,<br />Shane

 

[Tom Scully]

Re: 1977 Johnson 140 No Spark

Sounds like the power pack, I believe that terminal should have the same voltage as the primary side of the ignition coils while cranking. It should not be grounded with the key in the run position or with the blk/yel wire disconnected.

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

Tom,<br />I do not know much about powerpacks. If the blk/yel wire is grounded with the key in the off position, it tells me that that wire grounds the pack out (kills engine). when you turn the key to the on position it ungrounds the blk/ylw wire. As soon as I start cranking on it the blk/ylw wire grounds out again preventing the pack from engergizing. I removed the wire from the pack to isolate everything down the wire (harness, key switch, etc.). With the wire removed, the terminal still grounded out when cranking, so I made the assumption that is was something wrong with the pack on up stream to the stator. I need to do some homework on exactly how everything works and how to test it, but beleive I am on the right track.

 

[Tom Scully]

Re: 1977 Johnson 140 No Spark

It does sound like you are right on track.<br />Good luck, please post the results.

 

[Seasport]

Re: 1977 Johnson 140 No Spark

Shane, when you say that the kill terminal on the powerpack is grounded when it is disconnected from the blk/yel kill wire and the engine is cranking - do you mean that you measure 0V with your meter set to measure volts on this terminal or do you measure 0 ohms with the meter set to measure ohms? I presumed you were trying to measure ohms. There's a big difference.<br /><br />I think Tom is right re the voltage that you should measure on this terminal.

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

Seasport,<br />I was measuring continuity (ground) on that terminal. When cranking the meter would beep indicating ground. I had one probe on the blk/ylw wire terminal other probe grounded on block. I didn't measure voltage or ohms, because by not having any idea of what ballpark the values should be, it would not have told me anything. I was merely trying to troubleshoot the key/kill switch when I noticed the blk/ylw wire was grounding out when cranking. I am not a pro with this meter, and honestly don't know what a majority of the settings are for. I am used to an old fluke autoranging meter that I used for years, but lost it recently. I have done quite a bit of reading and research over the last couple days, and am looking forward to getting down there poking around and trying a few things this weekend (weather permitting). You, MCM, and others have posted some very helpful links and advice and I really appreciate it. Hopefully I will find the problem, or at least be able to post some additional data that may standout to someone who could pinpoint the problem. Thx again guys!!

 

[Seasport]

Re: 1977 Johnson 140 No Spark

As I said, I don't think using your meter to measure continuity in this way is telling you much. You're still basically measuring ohms - just with a beep added when there is low resistance - and you're hanging off the end of an active circuit with voltage on it (normally).<br /><br />You should be able to do the ohm tests OK using your meter. You'll need to set it to the resistance/ohms position. However, the voltage tests require a DVA meter or DVA adapter for a standard multimeter. This is because the voltages are not DC (i.e. steady) and not uniform AC either. Rather they have peaks generated as the magnets in the flywheel run last the coils in the stator & timer base. The DVA meter is designed to read the peak voltage.

 

[HOUSTON1]

Re: 1977 Johnson 140 No Spark

Seasport,<br />What you are saying makes sense. I will look into a DVA adapter. I am slowly starting to understand how everything works and "communicates" to each component. I appreciate you taking the time to give an explanation.

 

[kevin88]

Re: 1977 Johnson 140 No Spark

In my opinion going from the lack of spark while the kill switch wire is disconnected from the power pack I would say that the pack is definetely bad. From my own experience I can say that it is common for these packs to go during periods of extended use if something else is bad and causing spark to feedback into the pack or just making too much heat. In my situation it was a bad spark plug boot that killed the pack. But this can also be caused by bad spark wires or ignition coils. A visual check of these is a must. If the coils are cracked and material has oozed out of one of all of them I would replace them. If the ignition wires are rotted or cracked I would replace those as well. Keep in mind that replacing everything, meaning all ignition coils, wires, and boots will probably cost less than just one more power pack so don't be affraid to replace them. Whatever problem you had that killed the first power pack is still there and waiting to kill the next, and so on...

 

[HOU-CHAP]

Re: 1977 Johnson 140 No Spark

** Formally HOUSTON1 **<br />All,<br />Since my last response I have taken the boat in to a mechanic to troublshoot my ignition problem. He told me it was the Power Pack, and also advised replacing the coils. I finally got around to replacing the power pack and coils today because of the beautiful weather. At first I couldn't get the motor to start, so I took the carbs off and cleaned them real good. I am now getting it to run, but it appears to have a bad miss and backfires out the prop exhaust every so often. With the throttle advanced, it runs missing every so often. With the throttle at idle, it will backfire/miss hard and eventually stall out. My first thought was to check the coil plug wires, because I had to assemble. Everythign looks good there. I have no knowledge of testing the PP, and since all the parts I bought were new, I just have to assume they work. What could be causing this miss/backfire problem? I read in other posts it could be dirty carbs or bad timing? The carbs look great and have been cleaned and blown out. I also noticed the tach is not working now . I know it receives it's signal from the rectifier (correct me if im wrong). I also know this could be bad news for the PP, and for that reason dont want to try and start the motor anymore. Please post up any ideas on what could be my problem, and things to look for and check. Could a bad recitfier be causing this problem? I am a little bummed out that I paid a wrench to look at my motor, and it is still not running right . I am just hoping to gert this baby running good again soon, so I can get back out on the water. Please post any suggestions. On a side note there is a "module' (for better lack of terms) mounted on the back of the left (looking form the back of the motor) cyl. head. For some reason I have never noticed it before. What is it? It is not in my manual. Attached are some pics of my motor in hopes it may make it easier to give advice. Thanks in advance for any advice !!!!!<br /><br />Shane<br />Houston, Tx<br /><br />

<br /><br />