Coil for b78 Evinrude 85hp

[Joe Dawson]

" Joe, I've got a '78

" Joe, I've got a '78 Evinrude 85hp, Model# 85899C, Serial#J0001188. I need to replace the coils. The coils listed in catalogs (Sierra #18-5176) are for the '78-84, but do not look like the coils on my engine. My coils look more like the part listed for the '76-77 model (Sierra #18-5192) or the '73-75 model (Sierra #18-5194). My coils have a round center section surrounded by a multi layer laminated "C" shape. The round center section looks like it is filled with epoxy and the spark plug lead is permenantly embedded in this center section. The coil called for in the catalogs is a plastic module with a plug in spark plug lead. I have been told in the past that the '78 model was a change over year and parts applications are quirky. Can you shed any light on the issue. Thanks in advance for any advice you can provide. Joe "

 

[joereeves]

"Joe.... I checked the OMC boo

"Joe.... I checked the OMC books and the Sierra books. The difference comes into being due to the eariler models having one (1) powerpack whereas the coils have a screw hole type terminal at the end of the orange primary wire.

The 1978 model has two powerpacks and the coils have plug in terminals.

Pertaining to the OMC numbers, the original coil number on your engine, and the following superceeded numbers are 581819-> 582330-> 582366-> 583737-> 584561 which superceeds into that plastic module that you speak of.

Bottom line is... use the Sierra #18-5192 or #18-5194 with confidence. You'll have to change the end terminal but that's no big deal, and it'll keep the engine looking original.

Joe

"

 

[Joe Dawson]

" Joe, you are truely a font o

" Joe, you are truely a font of knowlege. The situation with the coils actually goes back to last season when I was experiencing an intermitten, "non-reproduce-able", miss in the engine under load. I asked you about it and you recommended a very sensible course of investigation, spark, compression, arcing, etc. I found nothing until one day when I had to remove the motor cover when I was on the water. I noticed the powerhead was covered with water. After running around for a while with the cover off, I discovered water was shooting up out of the back of the powerhead. Turns out corrosion had eaten through the thermostat housing near one of the stubs where the cooling hose attaches. Did I mention the water the conductive salty type? Anyway, this was causing an occasional ignition short. It was also causing the coils to rust to high heaven. It goes to show how difficult it is to diagnose older engines that can be struck with freak problems. Your advice did cause me to get a fancy compression gauge that I will have for ever; any excuse for new tools! Back to the coil application question.....I see your point of keeping the engine original but I have opted for the new style coils because they appear to be more salt resistant. I have secured a replacement thermostat housing so the engine should not be getting doused any longer but I figured I would give the new style coil a try. Thank you so much for this response and those in the past. It is your advice that makes it possible for an amateur wrench to live with an older engine. Again, many thanks. Joe "