no spark on one cylinder

[fishinfool96]

I cannot get a spark on the bottom cylinder. I've checked the points(new last year) they are gapped corectly and look fine, visually the coils look ok. I'm not sure how to test the coils. The motor is a '72 40hp johnson, it has a flywheel magneto ignition. I also have a service manual in the mail, it should be here monday. I had the flywheel off and noticed that on the inside of the flywheel one spot is magnetic while the other is not, is this normal or should both spots be magnetic, or is the other spot the opposite side of the magnet, a little confused? I could definetly use a little help, cause I can't afford to take it to repair shop.

 

[HighTrim]

Re: no spark on one cylinder

Swap the coils first to see if the problem follows the coil, if it does, replace it.

 

[fishinfool96]

Re: no spark on one cylinder

Cant believe I didn't think of that, thanks. Looks like a lot of work though. Is their a easier way.

 

[DutchMerc]

Re: no spark on one cylinder

It's not a big thing to chang the coils; just change the signal-wire position and dan the sparkplug cables. Don't move the coils, just the cables.
Good luck.

 

[Vic.S]

Re: no spark on one cylinder

You've already swapped the plugs to make sure its not the plug, I hope.

Also try swapping the condensers if the coils are OK

It's got to be the breaker, the coil, the condenser, the Ht lead or the plug
but check the wiring to the stop switch as well

 

[fishinfool96]

Re: no spark on one cylinder

The breaker points are gapped at .20 they look good no pitting. I swapped the coils and the top cylinder is still firing but the bottom is still not as far as I can tell. This may sound stupid, I dont have a spark tester or a timing light so I held my finger over the boot on the wire, lol. Before I swapped coils the top wire poked me real good and nothing on the bottom. After the swap small poke on the top and still nothing on the bottom. Could it be just the wire, they look pretty bad? The condenser wouldn't cause no spark would it? Stop switch?

Dutchmerc, the coils are on the armature plate and the plug wires snake around on the bottom of the armature plate, then go into the coil under the plate. As for signal wire, I'm not sure what your talking about. Theirs a ground wire for the coil and another that goes to the breaker points, Thats it.

 

[DutchMerc]

Re: no spark on one cylinder

Exchange the wires to the breaker points, and the coils are triggered by the other points. Then swop the sparkplug-cables and you are ready to go. The "other" coil is now suplying the "other" cilinder.. If the problem is on the other cilinder, the coil is the problem.

Good luck.

 

[fishinfool96]

Re: no spark on one cylinder

Thanks for the help guys. I've decided to go ahead and give it new coils, points, condensers and plug wires. I already put a fuel pump kit and a carb kit in it. Should run like new, I hope. Played with it this morning and now have spark on both cylinders. I think the surface where the flywheel passes the coil was worn away too far. I adjusted the coil out toward the flywheel and presto, got spark.
One more question when I took the armature plate off it had oil or grease on the bottom, it also seemed a little sticky on the top where the points and coils are at. Could the top seal be leaking or is it normal for a small amout of oil to be present? It was really sticky/thick oil or grease. This is my first outboard so I'm still learning. How hard is it to change that seal, do you need a special tool that is impossible to find? I have a service manual in the mail, should be here tomorrow, wish it was in hand now. Thanks again for the help.

 

[fishinfool96]

Re: no spark on one cylinder

Well I got the parts in the mail today. Put them on after work today. Decided not to put the muffs on, I'm gonna take it to the lake tomorrow. I still think that the top crank seal may be leaking a little. The top of the armature was awfully dirty and sticky. This may sound stupid but is there oil in the powerhead?

I found a post in a search that said to put some lube oil around the seal and turn the crank. If there's bubbles then the seal is bad. I tried that but didn't see any bubbles so maybe it is ok. Wish me luck tomorrow. I will post the results.

 

[DutchMerc]

Re: no spark on one cylinder

I still think that the top crank seal may be leaking a little.

If the top bearing is bad, this can cause play on the crankshaft. Results; seal goes bad, and maybe in your case, the points are not operated as they should, or even not at all by the cam. Check for excessive play on the shaft!!! This could be where the trouble starts...