1974 135hp Evinrude no spark

Helping a guy out with his motor. He has no spark on any of the cylinders. He replaced the power pack and still no spark. When I showed up I found the rectifier to be shorted. Power wire had most of the insulation cracked , probably shorted. Could shorted rectifier have taken out new pack?

DVA Stator voltage around 225 Volts. Allother DVA readings checked out, EXCEPT SENSOR WIRES TO GROUND. Each one only measured 22 volts. My data sheet shows 150-400 from ground on sensor wire 1-4.
DVA sensor wire to wire ohm values and voltage were in spec.

Thanks for an information.

Re: 1974 135hp Evinrude no spark

The rectifier (and actually the battery too) is not connected to the power pack, so no it didn't kill it. The ignition system generates it's own electricity--the voltage from the charge coils.

EDIT: Have you tried it with the black/yellow kill wire disconnected? Have you checked for spark with the spark plugs removed? Too-slow cranking is a major "gotcha". It will crank faster with the plugs removed.

Re: 1974 135hp Evinrude no spark

There is another critical ignition component, the timer base. When the engine is cranked, it should also put out a small amount of voltage. Not sure just what it should be, but later models with similar bases should output 0.3 volts. There is a good online web source for ignition trouble shooting: cdielectronics.com. They may have additional info on this particular ignition system. That engine should be cranked between 200-250 rpm's in order for the ignition system to fire the plugs. As F_R stated, a weak battery/starter can contribute to slow cranking and a "no spark" condition.

Re: 1974 135hp Evinrude no spark

I did get back to motor today with new DVA. I could not pull flywheel to inspect. I did not have the correct bolts in my puller kit, but they looked like they should have been, unless someone changed the threads. I had 5/16 that looked like they should have worked. Any idea what size?

Anyway here is what I have with new DVA. All Plugs out. Battery fully charged, but I still don't know how fast the cranking speed is. Battery is only 625CCA
Stator charge brown to brown/yellow: 290 v
Trigger 1 to 3 1.5V 7ohms
Trigger 2 to 4 1.04V 7ohms
Ground to each trigger sensor wire while cranking. 0 Volts
Disconnected each trigger sensor wire and had a small voltage on pack.
Each sensor wire disconnected, tested to ground ohmed out infinite.

Any suggestions whith these findings?

Re: 1974 135hp Evinrude no spark

Have you compared your results to the cdi electronics guide?

Re: 1974 135hp Evinrude no spark

Yes,

I have. There should be voltage present from ground to each Trigger wire. I have checked to make sure pack is grounded.
It almost appears the pack is bad again or ther is not a good ground on pack. I know he has already replaced the pack but I am feeling he has to buy another one.

Re: 1974 135hp Evinrude no spark

Yes,

I have. There should be voltage present from ground to each Trigger wire. I have checked to make sure pack is grounded.
It almost appears the pack is bad again or ther is not a good ground on pack. I know he has already replaced the pack but I am feeling he has to buy another one.