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Potting Compound Melting
Posted: Fri Jul 01, 2016 1:34 pm
by Maestro
The potting compound (yellow goo) on the back of my ICM/ECU started to melt and drip down onto the bell housing during my last boat ride. Engine temp normal on the gauge. It was a hotter day than usual for us...we are typically in the mid 70s but that day was 80s.
My engine hatches are aluminum and heat up pretty good in the sun. I'm wondering if a combination of the hot, sunny day and the engine heat were enough to get the old potting goo to start melting.
Do I need to be concerned about anything?
Re: Potting Compound Melting
Posted: Fri Jul 01, 2016 5:13 pm
by jralbert
I don't think a warm day would cause your problem. In our region, 90 degree days on the water are common. Your aluminum hatches are also reflecting heat and shouldn't be cooking the bilge unless you've painted them black.
Something is going on in the electrical circuitry. If you have a laser temp gun to take a reading, that may help you pinpoint the exact trouble spot (the laser things are quite inexpensive and very handy for a variety of measurements). I heard of this once before on the forum but can't link you to the case. Try a search.
Re: Potting Compound Melting
Posted: Fri Jul 01, 2016 5:42 pm
by GB49
Typical failure with Chrysler ignition/engine control. The module needs to be replaced immediately. I replaced both engines and kept the old one as a spare.
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 9:46 am
by Maestro
GB49-
Where do you recommend purchasing this unit and what terminology did you use? Some people call this thing the Ignition Control Module, I've heard others call it the Engine Control Unit and Engine Control Module or just the ignition module.
Thanks...
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 10:11 am
by GB49
I should clarify my previous post. The control unit itself is probably ok. The gooo generally comes from the voltage regulator. Id have to look at the engine to refresh my memory...
The link below is what I have replaced in the past. The part in this link my not the the correct part # for you. This is just for visual.
http://www.go2marine.com/product/158051 ... 47527.html
This is the main link with the ballast resister and other ignition parts.
http://www.go2marine.com/category/17373 ... parts.html
Ill check the paperwork as soon as I get to the boat
-Karl
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 10:54 am
by Maestro
Just double checked the boat and it's definitely coming from the icm not the voltage regulator.
Is there a difference between the marine icm and automotive? Local auto parts store has one for $40 but I see it is over $100 at hurrikain marine.
Thanks for your help!
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 4:00 pm
by ericinga
IMO - there is no difference between the automotive and marine ICM. I buy the Autozone part. I believe the part number is CR109. While youre at it, replace the ballast resistor. It is part no CR105.
I tell them to use a 1976 Dodge Charger as the vehicle.
Eric.
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 8:05 pm
by bill
Just replaced both my ICM part # CR109. I purchased from Auto Zone. Thanks Ron Spies.
These are made by Wells located in Fond Du Lac, WI., but they have a manufacturing plant in Mexico.

bill
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 10:05 pm
by bill
ericinga wrote:IMO - there is no difference between the automotive and marine ICM. I buy the Autozone part. I believe the part number is CR109. While you're at it, replace the ballast resistor. It is part no CR105.
I tell them to use a 1976 Dodge Charger as the vehicle.
Eric.
On the ballast resister CR105 make sure the back is sealed.
The automotive one is open and should not be used in a boat engine room.
They do get hot and start to glow like a toaster.
bill
Re: Potting Compound Melting
Posted: Sat Jul 02, 2016 10:30 pm
by Maestro
Thanks everyone for your help! This forum is awesome.
Found an ICM and ballast resistor at a nearby O'Reilly Auto Parts store and installed them this afternoon. Fired up the boat and she's as happy as can be. Will hang onto the old parts as emergency spares for now.
Happy boating this 4th of July!