75 HP Johnson Stator or Flywheel Problem?

Chuck B.

Cadet
Joined
Jan 26, 2002
Messages
23
Have a 80 model 75 HP Stinger Has a problem of not firing on top and middle cylinders. I removed the flywheel to get a visual check on the condition of the stator (cracks, etc.). It appears that the flywheel has been rubbing against the stator assembly in one area. Has gotten hot enough to actually melt just a slight bit of the protective plastic around that area. Can this somehow be causing my problem? Can the stator assembly not be aligned properly? What does the magnetic ring inside the stator assembly do? Looks to me it may bee a timing advance device. This is SSOOOOOOOO much different than a 3208 Cat or Detroit Deisel, Ha Ha, but I'm slowly learning! Thanks for any help you can provide, Chuck B. :)
 

jegervais

Chief Petty Officer
Joined
Jan 18, 2002
Messages
646
Re: 75 HP Johnson Stator or Flywheel Problem?

The stator assembly on your motor has 2 functions - The stator windings (yellow wires) work with a rectifier to charge the battery and the charge coil windings (brown wires) supply the operating voltage to the entire ignition system. So no or intermitent spark on 1 or 2 cylinders is less likely to be a stator assembly problem. The other device you noted is called a timer base. It contains sensor coils which are used for timing purposes.<br /><br />Basically, the charge coil provides about 250 volts (AC), which is rectified and stored as DC voltage in a charge capacitor inside the powerpack. The sensor coils in the timer base provide a 2 to 5 volt signal to the powerpack to another device called a silicon controlled rectifier (SCR). The scr serves as a "trigger" to release the high voltage from the charge coil which flows to the ignition coil and well, you know the rest. There is normally 1 sensor coil per cylinder in the timer base and one scr circuit per cylinder inside the powerpack. <br /><br />A good service manual and thorough testing will determine what components are bad.<br /><br />-John
 
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