Acceptable Spark?

[Brew2]

1986 Evinrude 140<br /><br />Need a little clarification on what an acceptable spark looks like. In doing some trouble shooting I checked the spark on all four cylinders.<br /><br />Each had spark and could jump a 7/16th gap, however, the spark just appeared to be a thin blue line to my eye. No big "snap" or anything. Is this as it should be or would this be considered a "weak" spark?<br /><br />Motor runs fine at higher speeds, just has some minor troubles at idle and often bogs as you accelerate. Still leaning towards a fuel delivery problem, but after performing the spark check, I'm wondering if I should be looking more closely at that issue.<br /><br />Thanks.

 

[JB]

Re: Acceptable Spark?

Spark sounds fine to me, Brew.<br /><br />Carbs need a thorough cleaning, and check that your stator isn't binding.<br /><br />Good luck.

 

[KYHunter2]

Re: Acceptable Spark?

JB, I'm a slow typist, what he said. LOL <br /><br />I would say, if its a good blue spark your , ok.<br /><br /> It sounds like, fuel, carb problems.<br /><br /> Also plug gap can effect idle performance.<br /><br /> I'd check , fuel system from tank to carbs.<br /><br /> If carbs haven't been cleaned/ rebuilt in a while. ( 2 Years or more )<br /><br /> I'd rebuild them.<br /><br /> Good - Luck,<br /> KYHunter

 

[mikeyzx2]

Re: Acceptable Spark?

Hey Brew...<br /><br />In broad daylight the sparks I've seen were thin blue, however in the dark they were fairly bright. I watched my mechanic do a spark test on a Mercury and the sparks on the tester were jumping the gap, and they were just blue lines. A weak spark won't jump the gap, and likely be more of a yellow look.

 

[ob]

Re: Acceptable Spark?

How was the spark test performed Brew2.Did you actually use a gap adjutable tool or just estimate the gap to ground.Reason I ask is that there is a point at which it will not jump the gap and if handheld tested the gap and arc isn't consistent.Just curious.

 

[Brew2]

Re: Acceptable Spark?

Thanks everyone....feeling much better about my spark now.<br /><br />ob...used an adjustable spark check tool, so did have a consistent 7/16th gap.<br /><br />Thanks again all.<br /><br />Cheers.