Spark won't jump 7/16

[ZSBrownlee]

87 Johnson j40tlcud compression 145 on both cylinders. Carbs rebuilt, went from vro to straight fuel pump. New powerpack. Newer spark plugs. I've cleaned electrical connections. It starts great, idles great. Butterflies open fully. SPARK WONT JUMP EVEN A 1/8 inch gap. I don't get it. First time I took it out last season it ran great then I turned it off to fish. Then next time I tried to cranked it it would not achieve plane. Seems electrical to me but he'll at this point idk. Thank you so much guys

 

[racerone]

You say it " starts great "------And you say spark won't jump a gap of 1/8" ------What are the issues TODAY with this motor ??

 

[ZSBrownlee]

Those are the issues. It won't jump a gap unless it's a little less than an 1/8. However it starts in 2 seconds and idles ok, good mid range, however won't plane. It has a slight bog at WOT which I imagine has to do with the spark not jumping the correct gap

 

[racerone]

Hard to believe that it can only jump a gap of 1/8".------------Doubt that the bogging is a spark issue.-----What other trouble shooting have you done ?-----Post a picture of your spark test method / set-up.

 

[fireman57]

Are you sure that you have spark on all cylinders? They will idle on just one. If you do when was the last time the carbs were cleaned?

 

[ZSBrownlee]

I can't my camera on my phone is broken due to dropping it. However I remove the spark plug and connect the tester to the spark plug wire then the end of the tester to the block (multiple points of the block just to make sure it wasn't a bad ground) I've removed the spark plug wires while at an idle on muffs and the rpm is effected from removal on both cylinders. But doesn't cut off. I've tapped and held electrical connections to see if it effects anything however it doesn't.

 

[ZSBrownlee]

I cleaned and blew air through carbs 3 weeks ago. They have spark when I hold the spark plug itself against block. Not strong though

 

[racerone]

You can not tell anything about spark by holding the plug against the block.-----These ignitions will fool you.-----Tested for a 3/8" or more in the dark / at night ????

 

[fireman57]

Have you tried pumping the primer bulb when it does this? Could be a weak fuel pump or a small tear in the diaphram.

 

[ZSBrownlee]

Racerone I understand however some mentioned I might not have spark at all or something like that so I was just saying I had spark.

 

[ZSBrownlee]

Also I did spark test in the shade under carport around evening time. I have pumped primer bulb it doesn't do anything

 

[fireman57]

Get a 10 dollar open air spark tester at discount auto and use it. Let us know what it will jump