72 125 evinrude overcharging and missfiring

[slyshar3]

My motor has a misfiring problem, and it has stumped a couple of repairmen who say the motor is perfectly fine. I found out on my last trip (I had just installed my second starting battery because the first one fried) that it is charging at about 17 volts at full throttle. I read a post that said anything over 15.5 will cause a miss, but noone else explained how to fix it. I also found out that this system is unregulated. Anyone have any suggestions?

 

[R.Johnson]

Re: 72 125 evinrude overcharging and missfiring

You have a battery CD ignition system, with a 9 amp, unregulated charging system. This engine demands a good battery with a 750 CCA rating. First! all connections have to be tight, don't use wing nuts on the battery. All grounds at the engine must also be solid. As to where the ignition miss is coming from, on this system, sensor, rotor, distributor cap, high tension leads, coil, pulse pak, plus sensor leads to the pack because of there bending motion. You also may still have a clipper unit in that ignition system. This system can take time, and a lot of checking to pin point a problem. Your high voltage charging rate is probably a bad battery, but again! all connections must be solid.

 

[John Bett]

Re: 72 125 evinrude overcharging and missfiring

Thanls, R.J<br />Good information to know.

 

[slyshar3]

Re: 72 125 evinrude overcharging and missfiring

The battery is new, and is in great shape. It is holding good voltage. Can this extra voltage cause a missfire like the guy said? The battery, however, is a regular car battery that only has 535 cold cranking amps.

 

[R.Johnson]

Re: 72 125 evinrude overcharging and missfiring

You need at least 9 1/5 volts to that power pack when cranking. If you have a mis-fire with the engine running, you have to check all of the above. Again! there are a lot of components to this system..

 

[slyshar3]

Re: 72 125 evinrude overcharging and missfiring

Thanks fellas. The anti-reverse spring was really weak, but not broken. It is a little deformed and moves too easily on the shaft. I will replace it, but I am having a hell of a time finding one. Also, I used the wrong type of grease on the plug wire to distributor towers when I replaced the wires last time. I cleaned everything with a degreaser and alcohol, and will put it all together when I get the spring and try it again.