Johnson 30 Horse Ignition Problem

[Follybob]

I have a 1990 30 HP Johnson that has very little power and a poor idle. I checked the plugs and the bottom one is normal while the top was oily and wet. After using a spark gap tester at 1/2" the top sparks only occasionally while the bottom is consistent,healthy, and blue. Any ideas?

 

[tashasdaddy]

Re: Johnson 30 Horse Ignition Problem

probably bad coil, swap the coils, see if the problem follows the coil.

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

OK. Switched coil leads and both coils are capable of delivering the same good blue spark when connected to the lower cylinder coil lead. What's the next step?

 

[tashasdaddy]

Re: Johnson 30 Horse Ignition Problem

ok what does it do with them connected to the top? could just be a bad plug. you only have on carb, so it is not the carb. it has to either be coil, or compression. have you check compression?

 

[lindy46]

Re: Johnson 30 Horse Ignition Problem

Or a bad plug wire

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

OK. Using a spark tester the top cylinder was not receiving anything but an intermittent weak spark. The bottom was good.

I switched the coils. No change. Top still bad bottom still good. Concluded coils are OK.

I then switched the small single leads to the coils. The top began working bottom stopped working. Im thinking maybe power pack or trigger?

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

Bump

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

Update - Compression is good, Pulled carb and rebuilt. Main jet dirty but still no improvement. I'm would like to continue with the electrical diagnosis. Does a weak spark on one cylinder sound like a power pack to you guys?

 

[tashasdaddy]

Re: Johnson 30 Horse Ignition Problem

it sounds like a dirty connection or a bad ground. did you physically move the coils or just swap the wires around?

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

I did both. Coils are swapped in position now. Same thing, though. Wet plug on top. Spark thready and intermittent. On the muffs it will run semi normally only at about 1400 rpm with occasional misfires and pops thru the exhaust. At slightly higher rpm it cuts in and out badly. Max rpm no load is under 2000. Yes, I know not to rev it on the flusher I discovered this at the landing first. Carb is clear, flywheel keyway not spun, compression good.

 

[tashasdaddy]

Re: Johnson 30 Horse Ignition Problem

hate to say it, you've got everything right, i would go with a power pack. and cross my fingers.

CDI power pack http://www.iboats.com/mall/partfind...gd_poid=334581&gd_row=95&**********=679696471

OEM power pack
Product Details:

Part Number: 0583896
Description: KIT AY,PP CD2USL61
Pack Qty: 1
Dimensions: 6.15 x 4.10 x 4.00 (in)
Weight: 0.68 lbs
Equivalent Parts: 0584331,0584489

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

OK. Thanks for the back up on this. I will buy a power pack and cross all fingers and toes.

Rob

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

Do you think I should perform a stator test before I get the power pack?

 

[perkdp]

Re: Johnson 30 Horse Ignition Problem

Have you checked for a naked place in the wire between the charge coil, power pack and top coil that it may be grounding ?

 

[Follybob]

Re: Johnson 30 Horse Ignition Problem

I actually found one on the lead to the cylinder that is not firing right. Spliced it and experienced no improvement. Maybe this burned out the power pack? Hopefully not stator. Guess I'm ordering one tonight.