1986 35Hp Mercury no fire

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markhodges78

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Trying to figure out a no fire issue. The info I received from the local mercury dealer was testing the stator
Between black/white stator lead and engine ground should be 12-18 I'm getting 13 so good there. right ?
Between black/yellow stator lead and engine ground should be 3.2-3.8 I'm getting 3.154 this is low. correct ?
Between black/yellow and black/white stator leads should be 3.1-3.7 and I'm getting 3.017 again low. correct ? Are these numbers consistent with a no fire issue or should I be looking else where I am testing with a Fluke 116 TRUE RMS Multimeter

Thanks Mark
 
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markhodges78

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Also the alternator test leads between
gray and yellow alternator leads should be .65" I'm getting 0.5 and

Red test lead to either gray or yellow lead, and black test lead to engine ground should have no continuity and I have no continuity
So bad alternator as well ?
 
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Chris1956

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The CDI Electronics web site used to have a troubleshooting guide for your motor. There is also a lot of info on the web, some of it is even accurate.

You could buy a service manual. It could be a bad stator, bad trigger or bad switchbox or wiring. The wiring harnesses of motors that old are usually loosing insulation by now, if not replaced.
 
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markhodges78

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I have the pages from the manual on stator testing alternator testing and trigger testing which I was able to get from the mercury service manager.. the numbers above are the required spec and the archived numbers so I was just asking for thoughts on my results I could call the service manager and ask him but he's already helped a lot with the pages I needed
 
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Chris1956

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Gee, not many shops will work on a motor that old. If you plan to keep her, you will need the entire service manual. You will want to do a link and synch, as well as carb cleaning, rebuilding and adjustment.

There is probably a spec on alternator output when cranking at a certain speed. It likely requires a DVA, which you can build from instructions on this website.

You check the coil grounds?
 
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markhodges78

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Chris1956 said:
Gee, not many shops will work on a motor that old. If you plan to keep her, you will need the entire service manual. You will want to do a link and synch, as well as carb cleaning, rebuilding and adjustment.

There is probably a spec on alternator output when cranking at a certain speed. It likely requires a DVA, which you can build from instructions on this website.

You check the coil grounds?
Click to expand...
They won't work on it and I am waiting on a manual just locating the proper manual was a task
 
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markhodges78

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All the harness are actually in great shape no burnt or cracking wires which surprised me. The mercury switch and the ignition have been unhooked at the switch box. Going to order a dva adapter and check things while cranking...
 
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markhodges78

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Ok guys still looking for opinions on this issue before I dump a bunch of money into it ....

below are to pages from the cdi troubleshooting Manual along with my test results

Testing the stator low speed black/yellow to ground I got 3078 ohms
Testing the stator high speed black/white to ground i got 134 ohms

Testing the stator low speed with DVA black/yellow to ground I got 168 volts

Testing the stator high speed with DVA black/white to ground i got 7.5 volts

Now on to the trigger

Testing brown/yellow and brown/white I got 729 ohms
Testing continuity brown/yellow to ground is OPEN
Testing continuity brown/white to ground is OPEN

Testing brown/yellow to brown/white DVA I get 1 volt
Testing brown/yellow to ground DVA I get .65
Testing brown/white to ground DVA I get .80

I see conflicting information on the trigger DMA specs 1 document says 4+ volts and the other document says 0.5+ volts i have my info on the first chart highlighted

Any thoughts on these results would be great

CDI Test3.png

CDI Test2.png
CDI Test1.png
 
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markhodges78

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On both coils I'm getting 0.2 ohms across + and - side of coil and 863 ohms across primary side of coil and engine ground all are within spec's
 
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racerone

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No easy way for you to test at home.----You test all the pieces that feed the switch box.---If they are good then switch box is bad.
 
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