1986 Mercury Classic 50 - No Spark on Any Cylinder

[aleme1]

My 1986 Merc Classic 50 has been running beautifully for many years. Usually fires right up regardless of temperature. I took her out over the weekend to do some crappie fishing, and couldn't get it to start. The starter itself was turning perfectly, but it just spun and spun. Never once acted like it was going fire up. No sputter. No nothing. Took it home and checked all the plugs (gapless). They look great. Hooked up a spark plug tester, and none of the plugs are getting any juice. It's almost like the kill switch has been tripped, but I double checked it and it is fine. The boat has always been kept in the garage, so all of my wiring is in excellent condition. Looks new, to be honest.

I read through a few forums and found some advice to unhook the kill switch wire and see if it starts. However, I don't have an orange/black or yellow/black wire coming into the switch box that I can see.

I'm pretty mechanically inclined, but wiring, ohms, multimeters, etc. confuse the hell out of me. Instead of getting anything fixed, I just end up confused and frustrated. I realize I may have to pull out the multimeter at some point to figure out the problem, but can you guys maybe try to help me isolate this issue without doing a bunch of electrical testing first?

Are there any no-brainer things I could look for? Should I start at the controls or the switch box? Where can I find the kill switch wire under the cowling?

One more thing to note: sometimes when running at WOT, the engine cuts out. Almost like it's not getting gas. It bogs down, but then the RPM's rise and everything seems to be okay. This happens more often than not when out on the water. I'm not sure if my two problems are related at all, but wanted to note it.

Thanks so much, in advance, for any help/guidance you can give.

 

[Jkcckc2002]

Just a thought, If there is a mercury switch on ther the kill wire is connected inline with it. That way the mercury switch will ground it out if tilted too high.

 

[wrench 3]

Sorry to tell you but other than disconnecting the kill switch and a visual check on the wiring your into multimeter work.
Trouble shooting and tests are at http://boatinfo.no/lib/mercury/manua...-115.html#/208 starting at page 208. Hopefully your switch box looks the same as the one in the diagram so that you can find the kill wire. The wire should be orange.

 

[aleme1]

Thanks for the replies, guys. I will definitely check out the diagram mentioned above.

Let's assume for a minute that I remove the kill switch wire from the switch box, and the engine fires. Can I assume that I would need to replace the actual kill switch inside the control panel?

Also wanted to note: I've been having some trouble with the actual tilt switch both on the back of the boat and at the throttle control. It tilts up fine, but I have to toggle it a couple times to get the motor to start tilting down. Could this have something to do with the problem?

Thanks again!

 

[Mercurylips]

Aleme- I have had a problem with my Merc500 that sounds very similar to yours. I replaced my stator and the intermittent power problem went away. Up until that time I took things a small step at a time and covered all the little inexpensive fixes first. My motor was a product of neglect and lack of need to have it run out well since the PO lived on a "NO-WAKE" lake. I still have a few things to do to get it where I want it but now I can take it fishing. Your tilt trim should not be related to the loss of power problem, but I am, like you, no expert. The guys on this web site are excellent. Good luck.