Mercury Black Max 135 not charging

[Halfhitch]

I have twin 1988 135 Merc 2 strokes on my Laguna 23. Neither engine is charging. The previous owner had the ignition/charging system updated to CDI brand components. Along with it he installed 2 new AGM batteries. I am now trying to sort out the reason for no charging voltage going to the batteries. My first check was to see if the proper parts were installed and it appears that is so. In reading the installation instructions from CDI for the stator and the rectifier, it warns not to use a maintenence free, AGM or Gel Cell battery. This is mentioned in both documents. I highlighted the notation in the documents attached.

I know some of the older electronics could be damaged by removing a battery cable while the engine is running. To that thought, I found the previous owner had installed a new Blue Seas battery switch but he put in a switch that has a #1 and a #2 but no "Both". If the switch is moved between 1 and 2 while the engines are running there is a time there when neither is connected. No doubt this has been done while the engines were running. No way to know. Why this switch was chosen, I have not a clue. I will be installing a Blue Seas e series Dual Circuit switch with a SI series ACR.

My first question in sorting this out is, could the fact that the batteries are AGM could that be the reason for "no charging"? Could the AGM not excited the rectifier for some reason? Could the fact that I have run it with AGM batteries be reason enough to have "smoked" the rectifiers?
Thanks for any insight on this. I'm just trying to get things understood before I start just throwing parts at it.

https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-274-5456-S15.pdf

https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-154-6770.pdf

 

[blaster]

I have twin 1988 135 Merc 2 strokes on my Laguna 23. Neither engine is charging. The previous owner had the ignition/charging system updated to CDI brand components. Along with it he installed 2 new AGM batteries. I am now trying to sort out the reason for no charging voltage going to the batteries. My first check was to see if the proper parts were installed and it appears that is so. In reading the installation instructions from CDI for the stator and the rectifier, it warns not to use a maintenence free, AGM or Gel Cell battery. This is mentioned in both documents. I highlighted the notation in the documents attached.

I know some of the older electronics could be damaged by removing a battery cable while the engine is running. To that thought, I found the previous owner had installed a new Blue Seas battery switch but he put in a switch that has a #1 and a #2 but no "Both". If the switch is moved between 1 and 2 while the engines are running there is a time there when neither is connected. No doubt this has been done while the engines were running. No way to know. Why this switch was chosen, I have not a clue. I will be installing a Blue Seas e series Dual Circuit switch with a SI series ACR.

My first question in sorting this out is, could the fact that the batteries are AGM could that be the reason for "no charging"? Could the AGM not excited the rectifier for some reason? Could the fact that I have run it with AGM batteries be reason enough to have "smoked" the rectifiers?
Thanks for any insight on this. I'm just trying to get things understood before I start just throwing parts at it.

https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-274-5456-S15.pdf

https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-154-6770.pdf











https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-274-5456-S15.pdf

https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled Documents/Installation Sheets/IS-274-5456-S15.pdf

AGM batteries are known to melt down the charging system on these two stroke outboards. The batteries can not accept the high rate of charge. Check your wiring carefully and look for any melted or burnt wires. Look closely at the yellow wire from the stator to the voltage regulator. It took me two voltage regulators to figure this out.

Did your voltage peg before the system stopped charging?

Mercury recommends regular wet cell batteries with this charging system.

 

[Halfhitch]

Thanks for the help Blaster. I did some closer inspection and the engine with the new rectifier is charging. Showing 13.8V at 1100 rpm. I never saw the gauge get pegged on the non charging motor. I think this engine has not been charging since I got it. The port engine shows no charge and on closer inspection the rectifier is the old one. I got a bunch of stuff with the boat from the Previous owner and in it I found a new rectifier that he evidently hadn't got around to yet. I should get my new battery switches tomorrow so I will go through all the battery cables and make sure that is all kosher then I will install the new rectifier and give it a try. I will also swap out the AGM batteries for some flooded cell ones....that hurts.

 

[blaster]

I’m glad the stator isn’t blown. Talk about expensive. At some point it may be wise to pull the flywheel and further inspect the wiring where you can’t see.

Not to be alarmist but these things do sometimes catch fire.

 

[Halfhitch]

Hopefully it's OK. I have a book showing how to test it without removing it so I will do that procedure. I've got to look up how to test the voltage regulator also.

 

[Halfhitch]

I replaced the rectifier on the non-charging motor and it solved the problem. I hadn't been able to find suitable batteries that are flooded cell yet so I couldn't resist trying it out with the AGM ones that are in it. I am not going to take it out till I get that changed.

 

[blaster]

After replacing the batteries you hopefully won’t have any more problems but always keep some peripheral vision on the voltage gauge for bouncing from normal to high voltage. This is a tell the regulator/rectifier is failing. Fix it asap so nothing else melts down.

I will say that the CDI component is superior to the Mercury part I used in this one instance.

 

[Halfhitch]

Thanks Blaster. When I get the new batteries in and the new Battery switch and ACR, what should the maximum charge voltage be? The level at which I should feel a component is misbehaving.

 

[blaster]

Somewhere just below 14 volts. Mine puts out 13.8 volts. If you see 18 volts something is wrong.

 

[Halfhitch]

I bought new flooded cell batteries today and tomorrow I'm going to sort things out on the battery cables.
This is the schematic Blue Seas put out for how to wire the battery switch and ACR. Do you think it's OK to have both these engines hit the same post on the switch with the charging power? Battery switch is a e-Series 5510 Dual Circuit.

 

[blaster]

That I’m not sure of since I have a single setup. I imagine charging in parallel would be fine though.