72 Evinrude-no power to the coil from the amplifier

Daremetz

Cadet
Joined
Aug 22, 2006
Messages
7
Have 72 Evinrude with no power coming from the amplifier to the coil and in turn no spark to the coil. We have replaced the amplifier and and the coil still nothing on the voltmeter. Should we be getting power from the #5 post on the terminal block from the amplifer, blue wire, which feeds to the coil? If so we are not. Motor turns over but no spark . Help.

Dare
 

freddyray21

Commander
Joined
Jun 10, 2006
Messages
2,460
Re: 72 Evinrude-no power to the coil from the amplifier

I don't have a manual for those anymore, but I believe the purple wire should show power to the amp. Those are notorious for amps going out.
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: 72 Evinrude-no power to the coil from the amplifier

Ground the power pak sensor wire's leading into the pak as you crank the engine. What you are doing is shorting across the sensor wire's.
 

Daremetz

Cadet
Joined
Aug 22, 2006
Messages
7
Re: 72 Evinrude-no power to the coil from the amplifier

Can you be a little more specific about the sensor wire. You bolt the amplifier and there are 3 wires that connect to the terminal block. (Red, Blue and black) Blue went to #5, Red went to #8, black to ground.

Dare
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 72 Evinrude-no power to the coil from the amplifier

What is the model number of that engine? A 1972 what?
 

Daremetz

Cadet
Joined
Aug 22, 2006
Messages
7
Re: 72 Evinrude-no power to the coil from the amplifier

1972 Evinrude model 85193
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 72 Evinrude-no power to the coil from the amplifier

Model number 85193 ia a 1971 85hp Evinrude, not a 1972.

Check/test that pulsepack/amplifier as follows:

(Voltage Drop To Battery Capacitance Discharge)
( Pulsepack When Electric Starter Is Engaged)
(J. Reeves)

On the older Battery Capacitance Discharge ignition systems (1968-1972), the electric starter reaches a point, even with a top notch battery, whereas the starter will draw excess voltage/current/whatever which results in a voltage drop to the pulsepack. The cure is to purchase a diode which is capable of handling 12 volts and installing it between the starter terminal of the starter solenoid (NOT the battery cable terminal) and the wiring terminal that supplies voltage to the pulsepack.

The diode must be installed so that the current flows from the starter terminal of the solenoid to the pulsepack... NOT vice versa. When that diode is installed in this manner, when the key is turned to the start position, the voltage that is applied to the starter is also applied directly to the pulsepack via the diode effectively eliminating the voltage drop and energerizing the pulsepack with the required voltage needed for its proper operation.
********************
(Battery Capacitance Dischage Powerpack Test)
Various OMC Engines - 1968 to 1972)
(J. Reeves)

Purchase a small 12v bulb at your local automotive parts store (the 12v bulb is to look like a flashlight bulb, not a headlight bulb). Solder two wires to that bulb, one to the side of the bulb (ground), and the other to the positive point. You might use a bulb of a somewhat lower voltage to obtain a brighter glow... just a suggestion.

Remove the spark plugs. With the key in the on position, make sure that you have 12v going to the pack at the terminal block (purple wire). Now, connect the ground wire from the bulb to any powerhead ground. Connect the wire from the positive point of that bulb to the powerpack wire that is connected to the coil wire on the terminal board (blue wire).

Crank the engine and observe that bulb closely (CLOSELY!). If that bulb glows even the slightest bit, the powerpack is okay. It may be a very dim glow... just so it glows! If it doesn't glow, the pack has failed.

Keep in mind, that type powerpack (Battery Capacitance Discharge) demands a top notch battery of at least 70 amp hours. Any less will, in time, cause powerpack failure.

That model has ignition points, not a electronic sensor. The points should be checked on "all" lobes so that they are set to .010, with no wider reading than that. Sometimes there is a slight difference in the lobes on the crankshaft.

For example.... having the points set so that on one lobe the point sets to .010 but on the second lobe it sets to .009..... that's okay. BUT having that same point set to .010 on one lobe and on the second lobe set to .011 is not!

Let us know what you find.
 
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