1977 Johnson with no spark

RoughFishAssassins

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First off I want to commend the members of this sight, alot of useful info here, but possibly not quite enough.
I recently purchased a 55HP 1977 Johnson. I got this at a good deal and am now in the process of putting it on my pontoon. The problem is that it doesn't have spark. It has about 140 psi compression on both cylinders, and turns over great. My question is where do I start to look? I have a multi meter at hand for any electrical areas. Not to mention a good assortment of tools to work on this, but I don't have DIRECTION. Please help me out, I greatly appreciated you words of wisdom.
Thank you
 

oldcatamount

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Re: 1977 Johnson with no spark

Probably bad coil(s). Are the coils mounted on the outside of the motor near the plugs? If so, look them over for cracks or burning. The cracks can be repaired but burning cannot. There is a driver coil under the flywheel, however, they very seldom will give you any problems. If you take the flywheel off, change the ignition points and condensers. I strongly suggest that you invest in the repair manual for your motor espeacially if you plan to keep it.
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

I got a little info from a mechanic, we all know how much they like to give away free, but he said that the power pack might be bad, more than the coils by the spark plug. Is there a way that I can check this, I know it is around $120 and would like to know if it is shot before spending money on something that it isn't??
 

bktheking

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Re: 1977 Johnson with no spark

Take your kill switch out of the equation and retest, kill switch grounds out the powerpack to kill the motor, if not the kill switch then stop on the ignition switch or shift switch.

This motor has no points , no driver coil's under the flywheel , it is a CD ignition, old school powerpack.

5 things could be doing it:

Bad wiring/ground
bad switch=ignition,kill
bad powerpack
bad stator
bad trigger

There are you items to check and in that order. You will need DVA or peak reading meter to check some of the parts.

Link to troubleshooting guide

http://issuu.com/cdielectronics/docs/troubleshootingguide/35

Hope this helps.

EDIT: add possible bad rectifier and possible bad battery to the equation.
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

Thanks so far, now you mention a kill switch, where would that be, or what wires should I be looking for??
 

bktheking

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Re: 1977 Johnson with no spark

It may or may not have one, usually a lanyard switch sticking out of the controls, not all controls have this kill switch.
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

OK no kill switck to speak of, could the wiring on the key be wrong? and is there a way to check the power pack, stator, and where are the triggers and what do they look like? I reall appreciate all the help. And also, what would you guys do, try to figure it out your self, or would you take it in? I am alright mechanically, just need to know what is wrong and I can fix it. Or should I possibly start buying new parts and replacing what might be wrong, I would rather avoid this and just spend my money on what is wrong.
 

bktheking

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Re: 1977 Johnson with no spark

You need to study the guide link I sent you and systematically eliminate the problem. Yes you can check all of those items, the tests are listed, you may need a dva. Don't spend a dime until you figure out what component is the issue (less the DVA of course) . Start by disconnecting the kill wire going to the powerpack. If that isn't it, test the pack. If it's not the pack test the stator and so on.
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

THANK YOU THANK YOU THANK YOU, I followed the order of elimination on the link you gave me and the it seems the rectifier is bad. At least it gives me spark. Now to find a replacement and try again.
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

??? Now after calling around, one of the dealers I talked to said that it was highly unlikely for it to have gone bad, he said he has never seen it. Could this be right?? Might it be something else???
 

bktheking

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Re: 1977 Johnson with no spark

That's BS- rectifiers pop all the time, people reverse the battery cables by mistake and that will take out the diodes in the rectifier, that is likely what the previous owner did. When I bought my boat the rectifier was toast, it wouldn't charge, as soon as I replaced it presto 13.5+ Volts. You can do like I did and get a 30A rectifier from your nearest electronics parts store (radio shack) and replace it with that, 1 wire goes to red, 1 to ground and the other 2 are yellow, it was like $7 to fix it.
 

eavega

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Re: 1977 Johnson with no spark

That's BS- rectifiers pop all the time

Yes. The last two motors I have acquired have both had to have the rectifier replaced before they would charge correctly. Turns out that on my last motor the PO had gotten a little sneaky and re-wired at the terminal board so the Tach worked AND the battery showed a charge even though the rectifier was blown. I'm not sure what results this would've had, but I do know that my voltmeter was showing as much as 16 V when the motor was running. Luckily I have no real electronics on my boat to speak of.

-E
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

OK dont know what happened, but went against my judgement and went back and checked more things, not sure what happened but it is up and running now. Thanks alot, you guys rock
 

bktheking

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Re: 1977 Johnson with no spark

Coulda been a loose wire and as far as the one guy who said "he said he has never seen it" bet ya he'd offer to look at it for you to trade for some cash :D
 

RoughFishAssassins

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Re: 1977 Johnson with no spark

Oh ya, he would do it for a trade. Now Ive run into the problem that it doesn't always spark. We took it out last night and it started but shortly died, and after that it wouldn't fire again, later we tried again, and it did the same thing, firered then died and wouldn't fire again. Once again we tried later and actually got it fired and off the lake. So what does that sound like??
 

bktheking

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Re: 1977 Johnson with no spark

I figured you'd be back, go back to the drawing board and test. Spark coming and going is a failing component or a wiring issue. Could be as simple as a failing ignition switch or as complicated as a internally broken wire in which you will have to hunt it down, let the testing begin.
 
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