Help, Gremlins in my ignition system!

[fishhard]

Here is the background: the engine is a 1975 85 evinrude I have been chasing down a problem with intermitent spark that started on the number 1 cylinder and now has moved to all four. Battery is new and fully charged. It will no longer run. I swapped out a power pack with a good running engine-no change. The coils had hairline cracks so they were all 4 changed with new.

The black/yellow wire from the key has been disconnected to eliminate key related issues.

I noticed that I would sometimes get spark if the warm up lever was up but it would stop if the lever was moved.

If I applied pressure to the wires from the timer base (where they move) I could sometimes get spark so I removed the entire timer base to check for shorts and all wires test good even when moved around, pulled etc...

The resistance from sensors 1 and 3, and from 2 and 4 both read 8 ohms (the manual calls for 10 to 20 ohms)

The Stator coil and flywheel showed a sign of a scratch probably from a grain of sand or metal shaving that I enlarged slightly for the photo:

Now for the questions:
1. Is the air gap between the flywheel and the sensors adjustable on this engine and is it possible this is the issue?

2. Is the stator shot given the scratch?

3. Is the timer base bad given the resistance of both of the sensors is 8 as opposed to: 10 to 20?

4. Am I missing something?

Please help as I am by no means a mechanic and could probably afford a newer used outboard but the lawyers fees, alimony and child support I would have to come up with prevent me from shopping for one.

 

[Joe Reeves]

Re: Help, Gremlins in my ignition system!

A scratch isn't going to cause stator failure BUT check it for the proper ohm reading (service manual).

There are driver coils at the extreme front and rear of the stator that emit approximately 300 volts to the powerpack capacitor. If either of those two areas appear to be oozing a sticky substance out of the stator, replace it as that creates a voltage drop to the powerpack.

If the stator's appearance and ohm readings are okay, I would assume it is good.

The engine must crank over at least 300 rpms in order for the stator to energize the powerpack (spark). A spark test must be done with the spark plugs removed (spark must jump a 7/16" gap.

A slow cranking engine will have either weak, erratic, or no spark. Slow cranking...... weak battery, poor connections, cables failing internally, or a failing electric starter.

 

[fishhard]

Re: Help, Gremlins in my ignition system!

A scratch isn't going to cause stator failure BUT check it for the proper ohm reading (service manual).

There are driver coils at the extreme front and rear of the stator that emit approximately 300 volts to the powerpack capacitor. If either of those two areas appear to be oozing a sticky substance out of the stator, replace it as that creates a voltage drop to the powerpack.

If the stator's appearance and ohm readings are okay, I would assume it is good.

The engine must crank over at least 300 rpms in order for the stator to energize the powerpack (spark). A spark test must be done with the spark plugs removed (spark must jump a 7/16" gap.

A slow cranking engine will have either weak, erratic, or no spark. Slow cranking...... weak battery, poor connections, cables failing internally, or a failing electric starter.

Joe, Thanks for the reply as I trust your judgement, The stator looks good (no leakage) and checks out at 579 ohms

When the engine will spark it easily jumps a 7/16 gap on a tester with all four plugs removed but it sparks only occasionally by that I mean it may spark for 15 revolutions than stop

I am using a 800 cca deep cell battery purchased new last year and fully charged, I have a tach on my timing light but cannot read for the required 300 revs without spark but I would assume it's turning fast enough.


At the end of last season I lost spark to just the #1 cylinder while the boat was running that seems to point away from an issue caused by low cranking speed.

Is it possible or likely that the sensors on the timing base to be intermitent (it seems as though they would either be GOOD or BAD)? Are the timing sensors adjustable on the 1975 85hp? The sensors are both testing at 8 ohms as opposed to the recommended 10 to 20 could that be an issue?

In your past experience would a bad wire from the timer base be a likely issue?

I really appreciate your help on this.

 

[fishhard]

Re: Help, Gremlins in my ignition system!

After closer inspection the sensor gap is adjustable, I put everything back together tonight as there appeared to be no shorts in the timer base sensor wiring as previously suspected

After consulting my newly purchased manual the sensor ohm readings are within spec as are the stators (.8 -.8 and .579 respectively)

I am now getting no spark at all what has me confused the most is that yesterday with all 4 plugs out, the black and yellow wire removed, using a remote starter, I would visually verify blue 7/16 spark but as I advanced or retarded the timing the spark would stop completely, any ideas?

 

[fishhard]

Re: Help, Gremlins in my ignition system!

The original problem started with a fouled spark plug on the number 1 cylinder on a 1975 v4 85 hp evinrude. I got the boat back to the landing at the end of last season and let it sit (fast foreward till now). I cleaned all connections, charged the battery fully, I pulled all the plugs and checked spark with a tester spark was 7/16 and bright blue but intermitent on all but mainly on #1

since the spark was mainly bad on only 1 I replaced the pack-no change

I replaced all four coils with new as they were showing hairline cracks anyway-no change

I checked the output of the stator with a multimeter set on a/c volts and multiplied by 1.41 and obtained an acceptable reading so the stator was good

spark was now intermitent on all four, I noticed while pulling on the timer base wiring spark would return, I checked the resistance through the sensors and through the stator and found all good, I pulled the flywheel, stator and base to inspect the stator for leaks and the wiring for breaks especialy where the timer base wiring moves, found all good and reinstalled

I realized that all my testing sofar was done without moving the timing setting, with the fast idle up had good spark when dropped down spark would stop on all four completely (a clue) the pressure on the sensors when moving the timer base must be causing the sensor gap to change?

I pulled the timer base again and discovered the adjustments for the sensors, I set the sensors out to their stops inked them and checked the clearance, no rubbing on flywheel

Rechecked spark-great on all four, I hope this helps someone else

Now for the final questions:

The epoxy was still intact on the sensor adjustment screws and the base screws were tight so I doubt they moved.

Is it normal for the sensors to need adjustment?

Does having to adjust them indicate that the timer base is getting weak and should be replaced? I would rather fix it right than take a chance that it may or may not work for a while and leave me stranded.

Thanks all.

 

[R.Johnson]

Re: Help, Gremlins in my ignition system!

Rapair offer's a guage to set those sensors'.