1987 Classic Fifty, no spark

[MNhunter1]

Greetings all,

Looking for some guidance in troubleshooting a 1987 Classic Fifty, 45hp with no spark to any cylinder. I have a spare switchbox, stator, and trigger on hand, but would like to rule out any concerns with the cable/controls/kill switch before swapping things out.

I was advised to r/o the cables all together by directly firing the motor to check for spark by jumping at the starter, but haven't come across that recommendation anywhere else. Would this be recommended?

Here's a link to my Starcraft 16SS rebuild that this motor will be powering: https://forums.iboats.com/forum/own...tarcraft-boats/10520858-1978-16ft-super-sport

Thanks in advance!

 

[MNhunter1]

Also, short of purchasing one of those multi-cylinder spark testers, is there an easy way to check all four cylinders at once rather than going one by one?

 

[Watermann]

Only 4 plugs and wires to test for fire.Here are some test specs for your electrical components.

https://www.outboardignition.com/pa...hFpmydxJDC1V7ZHzylWiphHglUGpSRAKzNDQ2x8opwQSc

One other thing to check is the mercury kill switch on the motor The black and yellow wire that goes to the switch box is the kill circuit that closes the circuit to kill the motor. That wire is also the one in your controls that kills the motor.

 

[MNhunter1]

Thanks WM, I believe I have a good understanding of the coils, plugs, plug wires, and how to test them. I did try removing what I believed to be the the kill switch wire at the switchbox, but still no spark. The wire at the switchbox was a black w/ yellow tracer, but it looks like the wire to the actual kill switch is yellow w/ black tracer?

I'm a bit skeptical of my control cables/harness for the following reasons and want to ensure I've either got them hooked up correctly, or eliminated all together in my troubleshooting:

When I first hooked everything up, I couldn't get my tilt/trim to work from the switch on my Commander controls. The motor side of the harness was missing the 3 pronged plug, so I had to improvise and individually connect each wire from the motor harness to the plug on the control harness. In doing so, if I recall, I did have to experiment a bit as I wasn't sure which wire actually went to which harness tab and I seem to recall arcing something in the process. Ultimately, I bypassed the tilt/trim switch from the controls all together and just wired up a toogle switch directly from the motor which worked to raise and lower the motor. There are also some random wires from the harness which I'm not sure go where and I need a little guidance in ensuring things are connected correctly, leaving me reason to be skeptical that it might not be a contributing factor to my no spark issue.

Main 8 pin plug - pretty straight forward and have no reason to believe there is any issue between the motor/control connection.

Control harness has a four wire harness that terminates in a 3-pin plug (assuming for the tilt/trim) and 2 loose connections I'm unsure of. Harness consists of:

• Green wire - to 3 pin harness
• Blue wire - to 3 pin harness
• Purple wire - loose
• Black wire - loose

There is a third wire (Blue wire w/ white tracer) coming out of the three pin harness that is loose as well.​

From the motor, and currently connected to my bypass toggle, are:

• Blue w/ white tracer
• Red
• Green w/ white tracer

I believe these would typically be connected to the missing female 3 pin harness from the motor, correct?​

I also have a cable coming from the motor with a loose:

• Purple wire
• Tan wire
• Black wire

Not sure where these connect as well.​

I've got pictures on my phone, so I will try to add them in another post. (On my desktop now)

 

[MNhunter1]

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[MNhunter1]

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[Watermann]

The happy face plug off the controls, brown/tan is tach, ground and switched power is purple.

To add you can check the kill circuit for being open or closed with an ohm meter.

 

[Watermann]

Here's somewhat of a look inside the control box wiring set up. It won't even crank with the neutral safety switch messed up.

 

[MNhunter1]

So if I’m not running a tach, the purple/tan/black wires from the motor do not need to be connected, correct?

Or do those connect to the loose purple and tan wires from the 4-wire harness from the controls? What about that blue wire w/ white tracer coming off the happy face plug?

The motor will turn over from the key at the controls, just want to make sure everything is connected that needs to be.

Thanks!

 

[MNhunter1]

[No message]

 

[MNhunter1]

Okay, so here is what I think I have figured out.

The purple, brown, and black wire coming from the motor I can just leave unconnected as I have no tach.

The happy face 3-pin plug:

• The loose blue w/ white tracer from the plug connects back to the loose purple w/ white stripes from the main 4-wire harness.
• The loose brown w/ white strips(trim indicator gauge wire) from the main 4-wire harness is left unconnected.
• As I am missing the female 3-pin happy face connector from the motor, I am still not sure what to do with the red wire coming from the motor(along with the blue/white and green/white wires) for the tilt/trim harness. I have identified what pins of the male plug the blue/white and green/white wires should connect to, but it still leaves the red wire without a home.

I'll do some experimenting with the red wire and see if I can't get things to work, then should be good to move forward troubleshooting the no spark issue with a good degree of confidence that everything is connected correctly. Not sure the tilt/trim switch even matters for the spark, could probably leave disconnected completely, but something I needed to work through anyhow.

 

[racerone]

With no controls hooked up.----No battery hooked up to the motor.------Pulling the motor over with a rope you should see spark.----And power trim / tilt has nothing to do with spark.

 

[Watermann]

Is there a kill switch on your controls? I had to put one on mine so I didn't think yours would have one either. Another thing is the switch itself, it could be closing the circuit internally but you can test that with the ohm meter too.

The stator on that era of motor is notorious for being bad in the high side windings. No way all 4 coils are bad at the same time and normally the switch box going bad won't drop all cylinders so if you're going to start dropping parts in her that's where I'd start once you figure out nothing is wrong in the controls.

You can also test the electronics with that link I gave above.

 

[MNhunter1]

Tilt/trim switch is now fully functional from the controls! Success! Had to order a new multimeter today as my current one is not quite up to the task.

 

[MNhunter1]

I actually swapped out my power trim wiring harness with a NOS OEM one I was able to find. Decided to just go ahead and start replacing the switchbox, stator, and trigger since I had the replacement parts here anyway and reduce the chance of an unaddressed bad part inadvertently taking out another. Just waiting on my flywheel puller to arrive to tackle the stator and trigger, which hopefully will result in my spark returning.

I did r/o the kill switch and rectifier, but never actually did any further trouble shooting before starting to swap things out. My new multimeter arrived the day after I decided to just go ahead and replace things.

Fuel - am I hurting anything by turning over the motor to check for spark without the fuel line hooked up? Plugs are all removed and I have the lower unit in a tub of water for the impeller, but just wanted to ensure the lack of fuel wasn't going to cause any issues.

 

[The Force power]

Fuel - am I hurting anything by turning over the motor to check for spark without the fuel line hooked up? Plugs are all removed and I have the lower unit in a tub of water for the impeller, but just wanted to ensure the lack of fuel wasn't going to cause any issues.

1- Make sure that ALL Spark plugs are grounded while check for spark, the built-up electricity has to be able discharge
( you can damage the Electronics if too much/too long voltage not being discharged)
2- You can squired some WD 40 inside the cylinders if you're concerned about lubrication
3- Make sure the water-level in the bucket is about 2" above the height on your water-pump
(not just deep enough for intake ports, water pump is not self-priming)

 

[Watermann]

There's no extreme forces involved in the motor only turning over and not firing. That being said I would feel better about it if the motor hasn't been run in a long time I would turn it over while spraying fogging oil into the carbs and a shot in the open plug holes as well.

 

[MNhunter1]

Flywheel puller finally arrived yesterday afternoon. Swapped in the new stator and trigger and had spark return on all 4 cylinders. Pulled her out in the driveway, hooked her up to the muffs, and after a little resistance, the ‘87 Merc fired back to life after over 10 years of rest. The rains came and back into the garage she went for some final touch ups, registration, and a future splash.