Ignition Problem with Merc 15 horse 2 stroke
 

I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. I've
checked the kill switch circuit and it appears to be OK. It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

Ignition Problem with Merc 15 horse 2 stroke
 

On Dec 17, 12:22*pm, Wayne.B wrote:
I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. * I've
checked the kill switch circuit and it appears to be OK. * It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

You didn't state a year, Wayne. Try this website, www.marineengine.com

Sounds like a Magneto problem ( the sending triggers), or coils, or
plugs, or wires for that matter. Good ground ( Coils)? Does the Motor
require a Battery, ie Electric Start? Clean system connecting
contact wires.....?

On a lighter note, I got duped into the old Snowmobile Ignition Test
once. Shocking experience to say the least. Ole' One-Lunger Rotax. You
could run them red hot, and they'd still go.

Good luck. I'm a backyard Mechanic, so that's all I can give you. Only
responsible for my Boat.

Ignition Problem with Merc 15 horse 2 stroke
 

On Thu, 17 Dec 2009 12:22:28 -0500, Wayne.B
wrote:

I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. I've
checked the kill switch circuit and it appears to be OK. It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

Well, disconnect the kill switch, keep it isolated from the block so
it can't make a connection and try it.

Other than checking the coil's ground, that's about it for me. Altough
I might try to find the trigger lead and see if you are getting a
firing pulse to the coil.

Unlikely to be the stator though - those don't usually go bad even on
older machines - they just don't generate enough electricity to become
unmagnetised. I'd suspect the coil myself.

Ignition Problem with Merc 15 horse 2 stroke
 

On Thu, 17 Dec 2009 14:49:24 -0500, wrote:

If you are getting a trigger signal and nothing is getting to the coil
it is usually the switch box but I would disconnect the kill switch
wire and hold it in the air before I gave up on it.
(grounded = kill)
I have a Selloc book for the old mercs (it covered my 1975 7.5hp and
the 402 40hp of about the same vintage).

I bought this motor new sometime around 1994. Somewhere around here
I have a triggered sweep 'scope. That might be useful if I knew what
to look for. Does the "switch box" store up a charge in a capacitor
and then release a pulse to the coils at the right time ? Any idea
how much a new switch box costs ?

Ignition Problem with Merc 15 horse 2 stroke
 

On Thu, 17 Dec 2009 16:10:11 -0500, Wayne.B
wrote:

On Thu, 17 Dec 2009 14:49:24 -0500, wrote:

If you are getting a trigger signal and nothing is getting to the coil
it is usually the switch box but I would disconnect the kill switch
wire and hold it in the air before I gave up on it.
(grounded = kill)
I have a Selloc book for the old mercs (it covered my 1975 7.5hp and
the 402 40hp of about the same vintage).

I bought this motor new sometime around 1994. Somewhere around here
I have a triggered sweep 'scope. That might be useful if I knew what
to look for. Does the "switch box" store up a charge in a capacitor
and then release a pulse to the coils at the right time ? Any idea
how much a new switch box costs ?

http://www.marinepartsplus.com/catal...803024/3234-30

You're welcome and Merry Christmas. :)

Ignition Problem with Merc 15 horse 2 stroke
 

On Thu, 17 Dec 2009 18:26:29 -0500, Gene
wrote:

I didn't get duped, but I DID get tangled up in an old one-lunger
engine's magneto, once..... you'll beat the hell out of yourself
trying to get away from it...

Remember the old electrolytic capacitor trick?

Or the flyback transformer trick?

Ah - those were the days.... :)

Ignition Problem with Merc 15 horse 2 stroke
 

"Wayne.B" wrote in message
...
I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. I've
checked the kill switch circuit and it appears to be OK. It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

The best thing I have found is to either have some relative or in-law who
you're not particularly fond of to help you. Hold the wire, make sure
they're grounded, and pull away on the cord. It will shortly (no pun
intended) tell you if you have spark. Trouble is, you run out of relations
that will help, because for some reason they will only help once. I never
suspected my mother in law knew so many cuss words or that she could hit and
kick so hard.

Please share with us what you find is the cause. I'd guess you have a wire
grounded somewhere acting as a kill switch.

Steve

Ignition Problem with Merc 15 horse 2 stroke
 

"Gene" wrote in message
...
On Thu, 17 Dec 2009 16:09:26 -0800, "Steve B"
wrote:


"Wayne.B" wrote in message
. ..
I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. I've
checked the kill switch circuit and it appears to be OK. It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

The best thing I have found is to either have some relative or in-law who
you're not particularly fond of to help you. Hold the wire, make sure
they're grounded, and pull away on the cord. It will shortly (no pun
intended) tell you if you have spark. Trouble is, you run out of
relations
that will help, because for some reason they will only help once. I never
suspected my mother in law knew so many cuss words or that she could hit
and
kick so hard.

Please share with us what you find is the cause. I'd guess you have a
wire
grounded somewhere acting as a kill switch.

Steve


You don't have in laws as stupid as mine..... dayum.... it done it
agiyun'....
--
Happy Chrismahanukwanzakah!










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the things you didn't do than by the ones you did do.
So, throw off the bowlines. Sail away from the safe harbor.
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Explore. Dream. Discover." - Unknown

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LOL.

Ignition Problem with Merc 15 horse 2 stroke
 

On Thu, 17 Dec 2009 18:28:17 -0500, Gene
wrote:

On Thu, 17 Dec 2009 16:09:26 -0800, "Steve B"
wrote:


"Wayne.B" wrote in message
. ..
I have an older Merc outboard that has always been fairly reliable but
went to start it the other day and it appears to have no spark. I've
checked the kill switch circuit and it appears to be OK. It has an
electronic ignition module on the side of the block which gets two
inputs from the vicinity of the flywheel and sends its output to the
coils next to the sparkplug wires.

Anybody have an idea how to troubleshoot it from here ?

The best thing I have found is to either have some relative or in-law who
you're not particularly fond of to help you. Hold the wire, make sure
they're grounded, and pull away on the cord. It will shortly (no pun
intended) tell you if you have spark. Trouble is, you run out of relations
that will help, because for some reason they will only help once. I never
suspected my mother in law knew so many cuss words or that she could hit and
kick so hard.

Please share with us what you find is the cause. I'd guess you have a wire
grounded somewhere acting as a kill switch.

Steve


You don't have in laws as stupid as mine..... dayum.... it done it
agiyun'....

LOL!

Gene, you don't reckon your in laws are telling the same sorts of
stories about *their* in laws, do you?
--

Have a Super Christmas and a Spectacular New Year!

John H