Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then sat

[biglsells]

I've had this motor for several years. Used it a couple years ago and it worked just fine then I set it in the barn and it sat for two years. Took it out to clean it up and sell it off and when I removed the cowling there was a nice mouse nest encompassing the two spark plugs. Cleaned that out of there and got it pretty but still would not start so I assumed the carb needed to be re-done but thought I would check for spark. There is no spark on either cylinder. I have ruled out the kill switch by disconnecting it. I have trimmed the plug leads and put on new plug boots, still nothing. Pulled the flywheel and cleaned the points, still nothing.

I have some basic knowledge but still very limited. With flywheel removed I see a coil and a couple condensors and then on the side of the motor two more coil packs, where would you start with this? Can any of these parts be tested with a meter and if so what would the readings be?

Thanks in advance to the gurus!

Lawrence

 

[orbanp]

Re: Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then

Hi Lawrence,

There are a couple of things that you could check out.
Here is a generic diagram of your ignition:

The LT coil is the "driver coil" item 18 on the parts diagram: Evinrude Magneto Parts for 1973 18hp 18304A Outboard Motor
Its resistance should be around 4 - 6 Ohms, or in that ballpark.
The HT coil, or ignition coil, item 44, that part that attaches to the LT coil has again about 4 - 8 Ohms resistance. The high voltage part, that goes to the spark plug, has about 5 - 10 KOhm, these you can measure with a DMM. Points should open and close, zero and infinite resistance. Capacitors should read infinite resistance with a DMM.
The gap of the point is also critical, before one set of points open, the other point should be closed, giving ground to the other end of the LT coil.
Usually there is a kill switch shorting the two ends of the LT coil (not shown in the diagram). If your motor has one like that, check if it is not permanently shorted.
Any chance that the mouse has chewed through any of the wires or other components?

Good luck, Peter

 

[biglsells]

Re: Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then

Hi Peter,

thanks for the reply! Drive coil is checking out ok. Cleaned and gapped the points again and started getting spark on the bottom ignition coil but no spark on the top one. Checked it out and the Ohms are way out of range so I ordered a replacement today on ebay, looks like I will have the motor running again soon.

Thanks again for the information!

Lawrence

 

[orbanp]

Re: Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then

Hi Lawrence,

Good progress!
One thing I forgot to mention. If the HT wire to the plug is a resistor wire, or the plug connectors have interference filtering resistor in them, then the resistance reading in the HT coil part (measured from the plug connector to ground) could go up by about 5 - 10KOhm.
On the other hand outboard motors usually never used interference filtering ignition components, but you never know.

Peter

 

[biglsells]

Re: Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then

Thanks again Peter!

Another question - once it's running, what is the value of a motor like this including a fuel tank?

 

[orbanp]

Re: Evinrude 1973 18304A No Spark on either cylinder - Ran 2 years ago just fine then

Hi Lawrence,

I guess the smart a** reply would be that your motor is worth as much as someone is willing to pay for it ;-)
Seriously, probably it is worth a couple of hundred of dollars, if it is running and is in good order. Try to look for similar outboards for sale in your area.
Buyers would be interested in how much is the compression in the cylinders, when was the last time the water pump impeller was replaced, and if you have any water in the gear case oil. They might even test the compression and look at the oil.
They would also look at the cosmetic appearance of the motor, and at how much the prop and skeg is beat up.

Peter