79 johnson 55 hp no spark

[jking88]

i am new to thi forum and just recently bought a john boat with a 1979 johnson 55 hp. the problem is i do not have any spark i pulled the fly wheel off and emery clothed the magnets but still nothing. i used a multimeter to check if there was any power coming from the coil wires but nothing. could these magnets go bad over time or the coils?

 

[fireman57]

Re: 79 johnson 55 hp no spark

If your coils have any goo leaking around them or are cracked you won't get spark. It is odd that they would all go at once. The magnets are probably not your problem. Have you had this engine running in the past or is it new to you?

 

[jking88]

Re: 79 johnson 55 hp no spark

no goo running out of the coils i had it runing about 2 years ago. i tested the voltage coming out of the flywheel wires and do not get anything. this is the first boat motor i have worked on.

 

[HighTrim]

Re: 79 johnson 55 hp no spark

If you have zero spark to start, locate the black wire with yellow stripe, disconnect it and re test your spark. If spark returned, your kill circuit has a fault.

Are you getting a good 250RPM when cranking? Any less and spark wont be there.

Testing the power pack and coils is a little harder, especially without a known good one. Do you have a DVA meter or adapter?

 

[jking88]

Re: 79 johnson 55 hp no spark

i am going to go try to find the black wire with yellow stripe. it has good cranking rpms. i dont have a dva meter but have fluke mutimeter

 

[jking88]

Re: 79 johnson 55 hp no spark

ok taking the black wire with yellow stripe off made the spark work on the bottom cylinder. thank you very much. the top cylinder still has no spark could this be a coil? i swapped the spark plugs and both work on bottom cylinder.

 

[HighTrim]

Re: 79 johnson 55 hp no spark

Ok you likely have a combination of 2 problems. First is easy to diagnose.

Your coil on the top cylinder is likely shot. Swap the coil, with the bottom cylinder. If spark now appears, you need a new coil.

Your main problem is that your kill circuit has a fault. Likely locations are the key switch, harness or shift switch. You may need to run a new kill wire temporarily and see if that cures it.

 

[jking88]

Re: 79 johnson 55 hp no spark

i switched the coils and both work now. loose wiring maybe on the bottom one maybe. i switched them back and the spark works now. i got the motor to run by pull starting it the starter wot turn the motor over fast enough to make spark. i am going to try cleaning up the terminals. thanks for the hep. where is the cheapest place to get a service manual?

 

[HighTrim]

Re: 79 johnson 55 hp no spark

Ebay. Get a used factory service manual. Do not get a clymer or seloc. They are junk. Glad you fixed it yourself, now hit the water.

Take all the wiring connections off pertaining to the starting circuit, and file them to a shine, then re tighten. This includes at the battery, starter, solenoid, and engine ground. Also check for nicks, cuts, and abrasions in the wiring. "Crunching" when you flex it is a sure sign of corrosion. VOltage drop testing is a good way to troubleshoot this.

 

[dan09]

I am currently running into the same situation. One day my engine was running and now it's not producing sparks on either of the cylinders. Should I replace the power pack?

 

[dan09]

Where do you disconnect the black wire with the yellow stripes from? . . .

MODERATOR EDIT: Please review the forum rule about posting to old threads. It is best to start your own thread rather than piggy-back your issue onto an existing (old) thread.

 

[saltchuckmatt]

They don't like when you piggy back on old threads. Start a new thread and others will give you advice.