1977 Evinrude 55hp coil test specs.

[Wetwilly62]

Looking for the actual ohms readings I should get when testing the primary and secondary . Lots of videos on this , just not with my actual coil. Any help is appreciated..

 

[racerone]

What is the motor doing / not doing.?----What other trouble shooting was done ?

 

[Wetwilly62]

Wont accelerate over 3500 rpm , fuel , carbs , exhaust, compression, link and sync good. Lower unit water pump all check good. All electrical components check good at idle. Just believe coils might be breaking down or weak with load or maybe power pack. Ran better initially, but after installing resistor type plugs ran worse each trip out. Read must use non resistor type. Changed plugs. Read that resistor type plugs can damage components. After installing new plugs brought rpms up to 3500 , before was 2700 rpm. .running out of ideas. Just like to check coils with meter. Just dont like spending money I don't have to racerone

 

[racerone]

Flywheel key checked ?

 

[Wetwilly62]

Flywheel key checked ?

Yes. Its there

 

[Bosunsmate]

Have you checked where timing advances too?

 

[Wetwilly62]

Have you checked where timing advances too?

Yes , timing advance is good. 19 degrees at 3500rpm

 

[oldboat1]

Probably 5 or 6K ohms from the plug boot to the ground wire (secondary side) -- but my reference is old style under flywheel coils. I would recommend measuring spark to test strength of the ignition system, just using a cheap adjustable tester. Start with about a half inch, and work back if you need to until you have strong measurable spark:

 

[Wetwilly62]

Probably 5 or 6K ohms from the plug boot to the ground wire (secondary side) -- but my reference is old style under flywheel coils. I would recommend measuring spark to test strength of the ignition system, just using a cheap adjustable tester. Start with about a half inch, and work back if you need to until you have strong measurable spark:

Have tested with that tool , jumps 7/16 gap nice blue spark .

 

[racerone]

If the flywheel key is sheared the timing will be off.-----Your timing light will still show timing to be correct however.

 

[Wetwilly62]

If the flywheel key is sheared the timing will be off.-----Your timing light will still show timing to be correct however.

Flywheel key is in place.

 

[Wetwilly62]

Update on coil specs should be 200 - 400 ohms across secondary . Mine are 1290 ohms.

 

[Bosunsmate]

Flywheel key is in place.

So you have checked that your #1 cylinder is at TDC when flywheel is at 0?

 

[Bosunsmate]

Update on coil specs should be 200 - 400 ohms across secondary . Mine are 1290 ohms.

Both coils are that? Thatd be interesting if both are out to that extent

 

[racerone]

Spark is jumping 7/16" gap but now you are suspecting you have 2 bad coils ?

 

[Wetwilly62]

Spark is jumping 7/16" gap but now you are suspecting you have 2 bad coils ?

Only posting my findings, have read a lot about coils breaking down under load.. just not sure where else to look. Also have read that bad plug wires are the biggest destroyer of coils, just thinking the high resistance spark plugs that were installed may have taken the coils out. Any other ideas just let me know just trying to figure it out

 

[Bosunsmate]

Well if you are sure they are out of spec then they are out of spec.
You could try cleaning the grounds too

 

[oldboat1]

The oem plug is L77JC4. Gap would be .030. (Maybe what you are already using....)

 

[Wetwilly62]

The oem plug is L77JC4. Gap would be .030. (Maybe what you are already using....)

That's what I changed to. Going to replace coils and see what happens.

 

[Wetwilly62]

UPDATE . after two new coils installed, much better , still coming up about 1000 rpms short. Now carbs want to load up when idling for a couple of minutes. Takes a minute to clear it up.. Any ideas ?. See video here
https://youtu.be/lZtQPGizXVE