1987 Johnson 15 HP J15RCUD Lost Spark

New to me 1987 Johnson 15 HP engine J15RCUD. I was told this engine hasn’t been run for 4 years. This engine has the newer style fuel pump p/n 399857, but early style carburetor with metal bowl. I understand this was a transition year for the new fuel pump and carburetor, but the carb is the older version.

On Saturday compression check on both cylinders = 112 psi, Spark on both cylinders jumping 7/16” gap. Engine fired up, ran and I purchased the engine.

Sunday, I placed the engine in a barrel and ran on new ethanol free gas with Stabil, Yamaha ring free and Mercury Quickleen normal dosages. Engine started shifted and ran fine for approximately 20 minutes with heads heating up to 163 degree F. Water pump seems to be working, but I plan to replace the impeller. I also plan to rebuild the carb. Engine died approximately 5 minutes after reaching 163 degree F

This 1987 15 hp has the cable type throttle with red kill button on end and man overboard lanyard switch on end.

No spark at either cylinder at this time. Any guidance on next steps to regain spark.

I have the “CU” 9.9 thru 30 Service Manual and performed the following tests:

Stop Switch Test – R and TE Models:
Meter correctly shows NO continuity with clip and lanyard installed.
Meter correctly shows continuity when stop switch assembly is pushed in.
Meter correctly shows continuity when clip and lanyard are removed.

Stop Circuit Test: I did not perform this test since I don’t have the “jumper wires” to make reliable pin connections. The above Stop Switch Test results should confirm functionality? Correct?

Charge Coil Ohmmeter Tests:
Charge Coil resistance is 563 ohms and within 575 +/-25 ohm range
Ground Tests: No needle movement (infinite resistance) testing charge coil lead “A” and “D” to ground

Sensor Coil Ohmmeter Tests:
Sensor Coil resistance is 39 ohms and within 40 +/-10 ohm range
Ground Tests: No needle movement (infinite resistance) testing sensor coil lead “B” and “C” to ground

I don’t have a C.D. Voltmeter, “Terminal Extenders” for the ignition coils, or a “Junction Box” for run tests, but I plan on completing the Cranking Tests using a friends Klein CL800 clamp on meter which I am told can read peak voltages. Will this meter work for these tests?

Any other thoughts on any additional tests or checks I should perform to find the root cause of my NO SPARK problem?

Where is the ignition module on that? Disconnect the black kill wire from the module

flyingscott said:

Where is the ignition module on that? Disconnect the black kill wire from the module

Click to expand...

I believe the black kill wire is the "E" terminal on the 5 pin Amphenol connector. If I understand, you are suggesting the "Stop Circuit Test" in the manual. Thinking I performed the "Stop Switch Test" to confirm kill circuit functionality, I was reluctant to pull the "E" pin from the Amphenol connector. Could I accomplish the same test by more easily removing the ground wire from the engine block/ground?

New powerpack fixes these 9 out of 10 times.

OK, I will order a new powerpack.
Also, once I get the Klein CL800, I will try and use it to measure peak voltages for the cranking tests.
Thanks!
PS; flyingscott, your avatar brings back memories. My father had a 7 1/2 HP Scott Atwater with Bail a matic. It was a fine outboard that served us well. I was always impressed with the bailing feature after a night of rain.

I performed a Stop Switch Test and checked the Ignition Coil, Charge Coil, and Sensor Coil resistance measurements. All resistance measurements met specification.

I purchased an Electronic Specialties Model 640 Direct Voltage Adapter for use with the Klein CL800. I checked and passed the Charge Coil Ground and Output Tests. I also checked and passed the Sensor Coil Ground and Output tests.

I performed a Power Pack Cranking Test using the DVA adapter. I had zero output voltage on both the Number 1 and Number 2 primary leads (spring clip in the boot leading to the ignition coil). I believe this test confirms a faulty Power Pack.

Racerone, You Called It!

I replaced the Power Pack and the engine fired right up! I'm happy I was in the 90% club for the above symptoms described! It's on to some tuning.

Thanks for the help!