1979 115hp Johnson weak sparks.

[Valv]

I have a 1979 Johnson 115hp V4. I started it yeasterday to decarb it. This morning after letting it soak overnight I cannot start it again. Funny thing spak plugs have weak spark, and if I attach all 4 (loose) to see if sparks occurs, they won't. I will go buy a spark tester tomorrow, but in meantime does anybody know what could cause 4 weak sparks ?<br /><br />Thanks.

 

[rickdb1boat]

Re: 1979 115hp Johnson weak sparks.

Did you install new plugs after the decarb?

 

[12Footer]

Re: 1979 115hp Johnson weak sparks.

One thing would be a starter drawing too much current. <br />A bad battery, not supplying enough current, or corroded terminals on the battery,solenoid or ignition witch.<br />Try pulling it thru (with the plugs out), to see if you have a hotter spark.

 

[DJ]

Re: 1979 115hp Johnson weak sparks.

Hey Valv,<br /><br />That decarb. chemical is VERY hard on spark plugs.<br /><br />Throw an old set in to see if it helps.

 

[Valv]

Re: 1979 115hp Johnson weak sparks.

Yeah, I noticed is VERY hard on plugs, I tried older ones and a new set. I just went outside while is dark and try to start it. No way. I have 3 batteries I alternate, while I try. It has 120lbs even all 4 cylinders, carbs rebuilt this winter (I haven't used boat yet, you know MN, lots of cold...).<br />It really puzzles me since I started it yesterday, doing a decarb as per instructions from you guys, let is soak overninght to give a second decarb with just a couple of hours soak.<br />Not a sputter, choked, not choked, spray mix into throats, tilt up, tilt down, pull plugs, crank it in case it was flooded, new plugs.... <br />I will pull flywheel tomorrow and check if crankshaft did break key and threw timing out.