1977 Evinrude 55hp coil test specs.

[Bosunsmate]

If you mean load up ie too much fuel you could check the needle and float are working properly

 

[Wetwilly62]

If you mean load up ie too much fuel you could check the needle and float are working properly

Didn't do this prior to changing the coils. Went with CDI COILS could there be that much difference than OEM.?

 

[Faztbullet]

OEM specs on coil are …..resistance primary 0.1 +/- 0.05 ohms...resistance secondary 1300 +/- 200 ohms

 

[Wetwilly62]

OEM specs on coil are …..resistance primary 0.1 +/- 0.05 ohms...resistance secondary 1300 +/- 200 ohms

Thanks Faztbullet. Just found that in the manual this morning. Question. the new CDI coils i installed normal resistance across secondary is only 300 ohms. According to their tech guy . OEM coils as you stated are 1300. Any idea What difference in performance of the ignition system those differences in ohms make.

 

[Faztbullet]

CDI uses a different size wire in coil winding and a powder formed ferrite..

 

[oldboat1]

With all of those out of spec readings, I would check my testing technique or equipment. Believe you should set your multimeter to 1K ohms for coil resistance measurements, for example.

Ignition issues aside, I wonder if you have either a cavitation or ventilation issue, maybe related to mounting height or perhaps placement of a transducer, or something affecting flow to the prop (hull style or condition, maybe, or prop condition). I’ll guess your boat doesn’t have much of a keel, but have your tried lowering the motor a half inch or so?

 

[Wetwilly62]

With all of those out of spec readings, I would check my testing technique or equipment. Believe you should set your multimeter to 1K ohms for coil resistance measurements, for example.

Ignition issues aside, I wonder if you have either a cavitation or ventilation issue, maybe related to mounting height or perhaps placement of a transducer, or something affecting flow to the prop (hull style or condition, maybe, or prop condition). I’ll guess your boat doesn’t have much of a keel, but have your tried lowering the motor a half inch or so?

Yes I have lowered and raised motor seems to perform best at its present mounting. Not the most ideal motor for this boat , it's a long shaft. But for 50.00 dollars figured I could make it work. The bottom of the boat is slightly dished in in the rear of the boat. Just fwd of and below the transom. Could this cause low rpm ? On the test equipment, I used calibrated autoranging fluke meter.

 

[oldboat1]

Yes -- a hooked hull can cause it to porpoise/fall off plane. Depends on severity.

 

[Wetwilly62]

UPDATE. Ran the motor today on the lake 2 gallons of gas with two cans of seafoam cleaner was happy with the RPMs 5000. After running out of the seafoam mix hook back to the regular mix gas tank dropped back to 3900 RPMs. Why does it run better with the seafoam mix other than gas?

 

[oldboat1]

should be running with a 50:1 mix.

Seafoam would give you a richer ratio (diesel fuel and solvents). Experiment with additional 2-cycle (but watch for plug fouling).

 

[Wetwilly62]

UPDATE After stator and powerpack replacement. Old Evinrude is purring like a kitten. Still no answer as to why it ran better on Seafoam mix. Thanks for all help