Low spark?

[Marty Lyle]

Mid 80's 150 Black Max. Lost power, had to idle home. Installed new plugs, same condition as follows. Starts fine,loads up and dies if any gas given. Removed each spark plug wire, with no sparking,not much change in engine idle. One ate me up with 2 inch spark, engine died.5 coils dead/ no. Ignition pack, not two at once! Would like help trouble shooting. Family dad, will get parts from E-bay, can do my own work, just don't want to waste time, should have my son fishing. Thanks Marty

 

[andy6374]

Re: Low spark?

So are you saying you have no spark on all the cylinders as of now?<br /><br />Before you dive into this, the basics need to be covered. An engine physical so to speak. Test the compression. If you have weak or uneven compression all the spark in the world is going to help you. Then move on to spark...<br /><br />First, get an inline spark tester or spark gap tester. Make sure each cylinder has spark or each spark can jump a 7/16" gap. It should be a bright blue snappy spark.<br /><br />Now its time for fuel related issues, which are mostly like carb and/or fuel pump problem related but we will get there on a "need to" basis.

 

[Marty Lyle]

Re: Low spark?

I was just pulling the plug wire from the spark plug while the motor was running. Only one #3, was throwing a spark. I will search for an inline spark tester as I leave work.

 

[Marty Lyle]

Re: Low spark?

I got the tester. 2,4,6,1 have proper spark. 3 has no spark, and 5 arks all around the coil to ground when hooked up to the tester. While testing #3, #5 was arking slightly to ground. These coils are original equipment 20 years old or so.

 

[KCLOST]

Re: Low spark?

I would switch the #3 coil with one of the other good ones(2,4,6, or 1) See if you get spark on #3.. If no change we will look at the switchboxes next...<br />Sound like #5 coil is toast.... Let's make sure #3 is also...

 

[Marty Lyle]

Re: Low spark?

I will try that this evening.

 

[Marty Lyle]

Re: Low spark?

Swapped wire #5 to coil #3, coil fires fine. I'm ready to look at the switch boxes. Took them apart to look for any damaged wiring. Non found.

 

[Laddies]

Re: Low spark?

Switch the boxes to see if the problem moves with the boxes or stays the same

 

[KCLOST]

Re: Low spark?

Yep, exactly as Laddies suggests...