35 mercury no fire

bigdaddysam

Recruit
Joined
Sep 15, 2008
Messages
3
I have an 86 mercury 35hp that ran fine 5 months ago when I parked it.pulled it out to give it a prerun before some thanksgiving rockfishing and no fire.I pulled the pluggs and grounded them and no spark. I wiggled all wire connections and the safety switch nothing.It will spin over though.Is there a part that will fail from sitting or are the connections prone to corrosion?What should I check?
 

bigdaddysam

Recruit
Joined
Sep 15, 2008
Messages
3
Re: 35 mercury no fire

I talked with someone today that siad it could be the switchbox.Is there a way to test it with a meter or the coils?I dont suspect the coils would die at the same time?What about the unit under the flywheel? If someone could help with this it would be great.
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: 35 mercury no fire

Make sure the tether switch is on, you can't test the box witout a DVA but you can test the rest of the system with a OHM meter and if it's OK then it's the box, heres the test from CDI
scan.jpg
 

mattmann1972

Seaman Apprentice
Joined
Nov 11, 2009
Messages
43
Re: 35 mercury no fire

Sounds very much like my problem, if it's not something silly like a kill switch playing up then i'll put my money on it being the stator, it's placed nicely under the fly wheel where it gets all the abuse of the heat from the engine plus it's the it's the first thing the weather runs into. Take the following wires off the switch box and measure the resistance using a DVA:

Blue to Blue/Blue White
Red to Red/Red White

You will have to unscrew them from the switch box before getting an accurate reading though. They seem to fail after the engine has been left for a while.

If you let me know what model your engine is i have the manuals to let you know what resistance you should see.

Matt

Weymouth, UK.
 

bigdaddysam

Recruit
Joined
Sep 15, 2008
Messages
3
Re: 35 mercury no fire

Thanks for all the help guys.After looking at the cost of a DVA meter I decided to roll the dice on the switch box.I got lucky and it worked Im thinking about buying a lotto ticket now.
 
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