40 HP only runs on one cylinder- COIL?? or something else??

[Greatlakesfisherman]

I have a 1985 Johnson 40 HP Model J40 RL COB- Runs on top cylinder only. Bottom cylinder spark plug looks wet but does not seem to be firing. Tried switching the coil wires around with no luck but not sure if I did it correctly. I also looked for any spark and could not see spark from either plug- even though motor does run on one cylinder. Compression is about 105 in each cylinder. Tried new plugs but still would not fire bottom cylinder.
Due to the wet bottom cylinder plug I think I am getting fuel to the cylinder through the carburetor but it is not firing so?I?m guessing that I have --A) a bad coil or-- B) a bad power pack.
Any help would be great to point me in the right direction.

 

[EN2]

Re: 40 HP only runs on one cylinder- COIL?? or something else??

Check your coils first with an ohmmeter. Also the plug wires.

 

[tx1961whaler]

Re: 40 HP only runs on one cylinder- COIL?? or something else??

A quick check is to swap the coils. If the problem follows the coil, then replace the coil. If the problem stays on the same cylinder with the coils swapped, then powerpack.

 

[Greatlakesfisherman]

Re: 40 HP only runs on one cylinder- COIL?? or something else??

Seems simple to switch the coils but maybe I have something wrong. I figured that I could just take the wires from the top coil and hook up to the cylinder in question. When I do this it still does not fire but sounds like it is trying to back-fire. I think this may be connected to the timing of the spark. I also tried swapping the plug wires and no success.

So at this point I think it may be the coil becase it seemed to "WANT" to start when I connected to the known working coil but it wanted to backfire.

Am I on the right track. Coil is about $35.00 and powerpack is about $110.00

I'm not sure how to check the ohms.

 

[tired evinrude]

Re: 40 HP only runs on one cylinder- COIL?? or something else??

do a spark check when you switch coils you have to switch wires to the power pack also.

 

[Greatlakesfisherman]

Re: 40 HP only runs on one cylinder- COIL?? or something else??

Thanks for the help guys. It turned out to be the powerpack and now it runs great.