88’ 135 Mercury Blackmax NO SPARK

[Rob2978]

Hi, I’m having issues with a 1988 135 Mercury Blackmax. Bought it last weekend. Didn’t have spark at first. Messed with it all day. And couldn’t figure it out. We even tried two fully charged batteries out of a 6.7 power stroke. And it would not spark. Next day I go buy a brand new marine battery and put it in then out of no where, spark. Sat for a week and tried to start again and doesn’t have spark. Charged batteries that were at 12.4V and still no spark. Changed trigger after old one broke. (Still no spark when old one was on). Maybe trigger needs adjusted but I don’t know that much.
Thanks in advance

 

[Chris1956]

Batteries do not produce spark in that motor. Spark is created in the stator, amplified in the switchbox and pulsed to the coils when the trigger fires.

I would check your wiring. It needs to be clean and tight. The black/yellow wires to the switchboxes (there are two on top of one another) kill the spark so disconnect them for testing.

 

[Rob2978]

I know coils are good I checked resistance with multimeter and they all checked out. I will disconnect the black and yellow and get back to you thanks for the quick response

 

[Rob2978]

Ok, I disconnected the black and yellow wires one on the outer switchbox and one on the inner switchbox. Still no spark. I did mess up and remove the flywheel fromt he spindle by the 6 bolts on top. When we got it. It had no spark so my in educated eye took it off without a puller to see if it was causing the issue. And we had spark after that and I moved it again and now no spark. Could that be the reason. I’ve had many people tell me that only changes timing. Which is understandable but I am not sure.

 

[Rob2978]

So I was wrong after disconnecting, spark has returned on switchbox side of motor. None on the left side per my friend since I’m away for the week.

 

[Rob2978]

So now with kill wires hooked back up still have spark on only right side. Had spark on both sides last week

 

[Chris1956]

Fix your flywheel position. See my other post.

If spark doesn't return, you could have a bad switchbox. They are best replaced in pairs.