1988 johnson 50hp power pack voltage output... STUMPED!

[ct1762@gmail.com]

I rarely get stumped, but hopefully one of you can give me some pointers. Got this motor in (j50BELCCD) and has hot blue 1/2'' spark. went through the usual ignition tests with DVA meter to make sure everything was good. well, tested primary coil output from the power pack to coils... waaa waaa only 3-4v when it should be over 200v. Suspected sensor coil... it was going to ground. replaced sensor coil with a known good one, and same thing3-4v at pack! then replaced the pack with a brand new one. same thing 3-4v. then got another good pack and same results (pack #3). checked and cleaned all grounds. nothing. then removed the flywheel and put another one on in case the original one had weak magnets (it was fine). nothing. still only 3-4v. I tried 2 different meters and both show the exact same reading! the charge coil is only putting out 45v when it should be 230v cranking, but fail to see how this would effect power pack output. ditto for disconnecting yellow wires at rectifier. but did it anyway and same results. the only thing i didn't do was disconnect the black/yellow stop wire at the pack. could that be causing these low readings? the odd thing is the spark is really blue and strong, with a big "snap". engine runs, too, but havent gone through the carbs yet so didn't want to run it long. any ideas guys?

 

[F_R]

If you are getting a hot 1/2" spark, I sort of don't believe your 45V is true.

Yes, a leak or short in black/yellow wire will result in weak or no spark. But that doesn't apply here because you have a good spark

 

[ct1762@gmail.com]

thanks. neglected to test the charge coil for grounding. got about 1.2v . looks like the sensor coil, stator and charge coil were out of spec. looks like i hit the jackpot with this one. anyway, just another reason hot blue spark can mean nothing!

 

[ct1762@gmail.com]

the 45v was for the stator, so i don't think that would effect power pack output at all. anyway, off with the flywheel for the 4th time lol. im sick of this thing already.

 

[racerone]

Really-----If you have 1/2" spark with a snap you can hear , there is not much wrong with the ignition !!----So what is your motor doing / not doing ?----What trouble shooting has been done on the other parts of the motor ??

 

[juno pierrat]

charge coil is at 45 volts , low like you said, ohms should be 575 +/- 25, you don't say if you changed charge coil, i've had mine go out , motor still ran, like crap and only 1800 rpms max

 

[F_R]

the 45v was for the stator, so i don't think that would effect power pack output at all. anyway, off with the flywheel for the 4th time lol. im sick of this thing already.

You are confusing me when you talk about "charge coil" and "stator", when talking about spark intensity. To me, the charge coil (s) charges the capacitor in the power pack. If it were only 45 Volts, there would be only 45 Volts being discharged to the coil's primary winding and you would have weak or no spark. Yes, it is supposed to be something around 300 V. The other coils on the stator are for charging the battery, not the power pack..

 

[ct1762@gmail.com]

you are correct... i made a mistake saying charge coil... meant to say stator power coils putting out 45v. The charge coil was putting out 243v, 1.2v going to ground so shes junk. 2/3 i used were like that, but got a new one. ill throw it in when i have cooled down my frusration lol. gonna do the stator/power coils while i'm in there. the whole ignition components look so absolutely mint i assumed they were good.

 

[ct1762@gmail.com]

Really-----If you have 1/2" spark with a snap you can hear , there is not much wrong with the ignition !!----So what is your motor doing / not doing ?----What trouble shooting has been done on the other parts of the motor ??

that's what i thought, but only getting 3-4v at ignition primary. it ran, just kinda lumpy and stalling at idle although that could be the carbs or the piece of balled-up masking tape used as an outer sleeve for the cam roller the previous genius used. just got it in on trade to refresh and flip.

 

[racerone]

I doubt there is anything wrong with the " spark making system " on this motor.------Perhaps some overthinking.----Improper use of a meter.----Testing the wrong wires ?-----Compression test numbers are ?----Checked flywheel key ( timing ) on this motor ?

 

[juno pierrat]

i don't think we've got one basic question answered, Does it run? got spark! got gas? spray something flammable in carbs, try to start, what happens?

 

[racerone]

I agree.------Do not tell us all the details of how you are testing this ignition system.-----It appears to be in perfect condition.----Does this motor run, yes or no ??---What trouble shooting have you done ?

 

[juno pierrat]

volts with DVA should be read on DC scale, get manual, 13 dollors PDFforless .con.. might want to start a new thread again, ct1762 is still looking for answers on this thread


MOD EDIT - Ivco's post was moved to his thread.

 

[ct1762@gmail.com]

I doubt there is anything wrong with the " spark making system " on this motor.------Perhaps some overthinking.----Improper use of a meter.----Testing the wrong wires ?-----Compression test numbers are ?----Checked flywheel key ( timing ) on this motor ?

The engine runs as stated above, yes. haven't gone through the carbs and replaced cam roller (old one held on by tape). my method is, as always, exactly as described in the service manual. i go though each ignition test in sequence with all of my motors. i make sure every system is working properly. As i said above, i did the charge coil ground test, and it read over 1 volt when cranking so according to the manual its either the leads or its grounding and needs replacement. it puts out 243v which is basically in spec (manual says 250v minimum) but its going to ground. I often use 2 seperate dva adaptors and multimeters if i'm not happy with the readings the first time. compression 135 #1, 125 $ 2 and thats cold after sitting for who knows how long. gonna get the new charge coil and see if the primary voltage reads over 200v after and post results here. its the only ignition component left so cant think of a thing else it could be. as i said, new old stock power pack and 2 other known good ones and all of them only show 2-4v at primarys. i have the stevens load adaptor, which is awesome, but is apparently not used on these ignition systems for this year. flywheel key is perfect... tried 2 different flywheels. thanks guys ill post results when i get the coil!

 

[ct1762@gmail.com]

also racer: i use an omc breakout box when i can. find it's much easier to not "screw up" and test the wrong leads!

 

[ct1762@gmail.com]

just an update: apparently pre-1988 packs are REVERSE polarity! just switched test leads and BAM! 200v on the nose. how on earth i figured that out was an accident ... hooked up my Dva adapter backwards. Now i can sleep at night lol.

 

[racerone]

If you are getting spark that jumps a 7/16" gap there is nothing wrong with the system.-----We told you that but somehow you thought there was something wrong with it !!!!!!

 

[ct1762@gmail.com]

I know... actually 1/2'' gap. I was simply trying to confirm values in the service manual. i've seen packs put out low voltage but still spark. the kill wire had 2.9v on it, which led me to believe it killed the other packs, but didn't. a compounding issue i guess.