Johnson 50 1996 2-cylinder. ? faulty ignition coil

[janul15]

My engine is BJ50 BELEDS. I have a long standing starting problem, I think it's the electrical system. (Compression is 150 on both cylinders, spark has been intermittent on top cylinder, and not jumping a gap of 7/16" at all on bottom cylinder). Tried to check most wires and components (I can't test the power pack). All good,I think, except the ignition coil resistances didn't match the specs in my manual, so I replaced it with a new one. Still got the sparking problems. Tested the resistance of the new coil, and they are the same as the one I replaced. The recommended specs. are; Primary Windings-0.05-0.15 ohms; Secondary Windings- 225-325 ohms. Readings from my ignition coils (old and new show ;Primary - 0.4 ohms; Secondary - 0.28 ohms. Meter is not the cheapest (Thsinde 18C). Have I done something wrong, or should I return the recently bought coil? Power pack is still suspect, but not yet tested or replaced.

 

[racerone]

New powerpack fixes it 9 out of 10 times.

 

[janul15]

Will replace the power pack. Have I fried the coil, or should I keep the newer one installed and try starting after only replacing the power pack?

 

[janul15]

Tried with new power pack. Same result; spark is good on the top coil, no spark on the lower coil. Swapped the plug leads around, same result, so it's not a problem with the leads. Moved the power pack leads to the coil around, still no spark on the lower coil. So I'm thinking; leads to the plugs (HT leads?) are O.K., and power pack O.K.. So the problem must be the coil. Or could it be something else?

 

[brodmann]

Have you tested the coil that is working correctly? Is it possible that you were sold a bad coil? Or is the functioning coil testing the same as the new one and the suspected bad one?

 

[janul15]

I have 2 coils. When either one is installed, I only get spark on the upper coil, no spark on the lower coil. I replaced the power pack after trying to start with the new coil. Could a bad power pack have damaged the coil?

 

[tphoyt]

Try swapping the plug and see if it follows.
It’s rare but a plug can fail from time to time.

 

[janul15]

Changed a lot of things, but I haven't changed the spark plug leads (HT leads). Does anybody know what specification and length of lead I need (I think 9"). The 2 on my engine are different lengths, and different ages. And what resistance should be shown on a DVOM, so I can check the new wires .

 

[janul15]

Updates to the thread. I believe the problem is intermittent. My tests on swapping round the spark plug leads should not have led me to believe that they were O.K. So, I'll replace them. I can revise my resistance readings for the coil; primary windings - 0.4 ohms; secondary windings- 235 ohms.

 

[janul15]

Here again, I'm afraid. Found various problems, and fixed them. But still not firing up. Compression good (150psi on both cyl.). Spark gap test good on both. Spark seen at both spark plugs. Flywheel key good and in place. Spark control rod set at correct spec. (2 1/2"). Sprayed Seafoam into carburettors, fuel is now seen coming from both cylinders. Using new clean fuel, premixed 50:1. Could I have an air leak causing a no start? One curious issue; when I push in the primer switch, I seem to lose a lot of power to the starter.

 

[tphoyt]

Maybe you’re flooding it.
Just for kicks pull you plugs and let things dry out and try agin without pushing the key in.

 

[janul15]

Flooding is a thought I'd had. I'll do as you say.