1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

[beretta5spd]

Hi all,

The story is last year a friend sunk my boat. I pulled the boat out of the water, pulled the plugs, and turned it over to push out the water. Reinstalled plugs and fired it up at idle for 10 minutes. Ran good.

Fast forward through a ridiculously cold winter (boat was stored indoors) and now I only have spark on 2,4,6. I hear that the most likely problem is the stator through my research but you all are the experts!

I hear that you can exchange wires on the switch boxes in order to check if it's the stator that's causing the issue. Attached is an image of the electronic ignition, if you could point me in the right direction in order how to do that it would be appreciated. If I am barking up the wrong tree please point me in the right direction. Any help would be appreciated.

Dwight

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

woops I should say that differently... It only has spark on cylinders 2,4,6. I did not try to fire it up yet. After more research I found out that it could be low voltage on the battery causing this. I know my battery is borderline at the moment... could this be the problem? or if I have enough battery power to spark from the one coil I should have enough to run both coils right?

 

[Chris1956]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

If that motor has the two-switch-box igntion (AKA ADI), the only electrical requirement is that the starter spin it fast enough to generate spark via the stator. Remove the spark plugs and energize the starter. Now test for spark on all 6. If still no spark on half, get on the CDIElectronics.com website and run the diagnostic tests.

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

Thank you Chris for the response. I'm curious if you can tell if I have ADI or CDI just by looking at the picture I attached in the original post. For some reason the www.CDIElectronics.com website wouldn't work for me this morning. But I did find this webpage: http://www.outboardignition.com/page39.asp which looks like I can test the stator and trigger with a voltmeter. Can anyone verify if I am on the right track? Thanks in advance.

 

[Chris1956]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

You have ADI ignition. There are some differences in ADI, based upon motors with less cylinders. Look for inline 6 ADI ignition with two switchboxes, which is what you have.

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

Thank you again Chris.

Just one more question for now.... when looking in the CDIElectronics troubleshooting manual it has different readings for the 9-16Amp flywheels and 40Amp flywheels (page 83). Can someone tell me how to tell the difference? I'm at work and don't can't just go take a look right now. Is it written on the flywheel somewhere if it's the 9-16 or the 40??

Thanks again,
Dwight

 

[CharlieB]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

You will need a DVA adaptor for use with your volt meter to properly test the stator.

The stator has two each sets of high and low speed windings, one each hi and lo for each switchbox. You can switch the red and blue stator wires between the switchboxes and retest for spark. If spark switches to the other 3 cyl's then you can be sure the stator is bad.

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

Thanks Charlie,

I just swapped the stator wires at the switchboxes (blue for blue/white) and (red for red/white). Turns out that the 1,3,5 cylinders were the ones to spark this time. As opposed to 2,4,6 previously. It appears that it will be the stator that needs replacing. I originally didn't like the price of the stator too much but then when I looked at the price to replace two switchboxes it didn't seem too bad .

On the weekend when I have access to a battery charger with a boost function I will use it to ensure I'm getting over the required cranking speed of 250 rpm. I may get lucky and find out it wasn't a high enough cranking speed and that is causing issues. Probably not, but you never know.

After that it looks like I'll be ordering a stator.

Thanks for your help guys

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

can someone help me find a part number for the stator???

1979.5 Mercury 115, Inline 6 - serial number 55*****

I found a stator off a 1985 Mercury 150 with a part number: 174-5456-16

I think it's very close if not identical. Will it cross over for my application??

Thanks in advance

 

[beretta5spd]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

I got home from work and decided I should post the actual serial number in case this makes a difference.

Serial number is: 5504837

 

[heroforlife911]

Re: 1979.5 Mercury 115, 6 cylinder, tower of power - only runs on 2,4,6

Not sure of the Mercury OEM# but I just looked it up in the Sierra parts book ... looks like we have the same engine.

Sierra Stator #18-5854

The book says it replaces OEM#398-5454A17 but I did a serial number look-up.
I would double check to make sure ... at least its a starting point.

Good luck,
Justin