No spark on bottom cylinder

htr2133

Seaman
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Jun 2, 2011
Messages
74
i thought I had this thing whipped, but I've lost spark again on the bottom cylinder. I double checked the plug wire connection. I had previously cleaned and gapped the points and I got good spark and the motor ran well but was still missing occasionally at high rpm. Since I had only shoved the plug wire back in without fixing the spring I thought that was why it was missing. I rebuilt the plug wires and I'm only running on one cylinder again. I checked compression and it's fine. So, I'm going to pull the flywheel again and need to know which ignition part should I replace first? I know the points are fine. Since I've had plug wires that were failing I'm guessing I should do that while nice got it off?

Thanks
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Can you swap the top spark coil with the bottom and get spark on the bottom then? If so then you've located your problem being a bad coil. If it still doesn't fire or spark, then you have something under the flywheel as your problem. If you already cleaned and set the points (or replaced them) and they look good. Then check the exciter coil and condensers. If a condenser is shorting out, it would not spark. So do a little testing and report back here with your results...
 

htr2133

Seaman
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Jun 2, 2011
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Good idea. I live five min from a BRP dealer so I ran and picked up a set of points and condensers and one coil. But, I will swap the existing coils before I do anything and test for spark again. If it's just the coil, I could return the other parts.

I don't have a meter to test the coils or condensers unfortunately.
 

bspeth

Senior Chief Petty Officer
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Aug 30, 2013
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I had the same problem,but it was the connection where the spike from the spring goes into the wire.I unloaded the spring enough to get 1/4" of stripped out copper in it and my spark returned.Not sure what type of wires you are running.
 

htr2133

Seaman
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Jun 2, 2011
Messages
74
I thought the plug wire was the issue too, but I actually held the wire firmly on my tester and rotated the flywheel and only about every 5th turn did I get anything at all. So when I do get spark it is very weak and won't jump a gap at all.

Top cylinder jumps a 1/4+ inch gap w nice blue spark. Bottom cylinder has been weak for some time. So, i am pretty sure I've got a bad coil or condenser or connection somewhere. The other possibility is that the point has moved again. When I pulled the flywheel the first time several weeks ago I had one point that was loose.

I'm headed to rent a puller today so I will report my findings soon.

Do you guys recommend replacing the plug wires while I'm under the flywheel? The parts place said they sell it off the roll. Pretty cheap I suppose.
 

AlTn

Commander
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Mar 9, 2010
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if this is the '73.. 6 hp..original wires?...42 years?...wires stiff and cracks becoming visible?....it's up to you....if you decide to replace them...do one wire at a time..loosen, don't remove, the underside armature plate clamps..may take a little wd to get the wires to slide by one another....as info...the spike in the coil has a slight corkscrew to it , so the wire should be twisted into the coil, not sure it makes that much difference, but that's what's called for
 

htr2133

Seaman
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Jun 2, 2011
Messages
74
Good to know! I'm a bit nervous to replace the wires. I can't see any damage to them but can't really see all of the wires especially where they connect to or touch arm plate.
 

htr2133

Seaman
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Jun 2, 2011
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Ok here is what I found/did:
1. Re-checked the points. The bottom cylinder point had closed the gap somehow. I re-gapped and cleaned. Put flywheel on hand-tight and checked for spark...nothing.

2. Remove flywheel again, remove coil for bottom cylinder. Wire looks grungy but no sign of damage really. A tiny bit of corrosion on plug wire at coil.

3. Installed new coil. Was difficult bc the wire was a bit longer and it kept wanting to get over on the shaft or in the way. Also had trouble making sure I had a good secure connection on the plug wire. But finally got it together where I felt good about it. Hand-tightened flywheel and got good spark but not always consistent. Figured that could just be my tester losing ground due to vibration.

4. Went to the lake, started ok, idled ok, ran awesome for about 5 min then it started to mis. Generally got worse and at times I was running on one cylinder w that bottom cylinder spitting and jumping in at times.

So....what should I check now? I have a coil/points tune up kit. Thought about just going ahead and replacing everything but I don't want to mess something up that is working currently.
 

AlTn

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did you clip ~ 1/2" off the plug wire at each end before reinstalling it to the coil and spark plug boot/terminal connection?
 

htr2133

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Jun 2, 2011
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Also, the parts store rep told me to make sure to use the new screws that came w the coil I bought bc the material used is different. But the new screws were too long. I felt they were going to damage something below the plate or keep it from turning.
 

AlTn

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post #6 comment #3..I've had to put a loop in that wire as well to get it to lay flat and stay out of the way..if you have the point set on hand..clean them first and install them for #2 cylinder...suggest you clip the coil end of the plug wire and reinstall....it's really no big deal to replace those plug wires...3' of plug wire will be more than enough... a little long on each wire is ok, but too much seems to get in the way when reinstalling the motor cover,etc.
 

htr2133

Seaman
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Jun 2, 2011
Messages
74
post #6 comment #3..I've had to put a loop in that wire as well to get it to lay flat and stay out of the way..if you have the point set on hand..clean them first and install them for #2 cylinder...suggest you clip the coil end of the plug wire and reinstall....it's really no big deal to replace those plug wires...3' of plug wire will be more than enough... a little long on each wire is ok, but too much seems to get in the way when reinstalling the motor cover,etc.

I need direction on exactly what screws/bolts to loosen to help me in replacing the plug wires. Your previous posts cautioned against removing the armature plate. I see several bolts and several screws on the underside of the timing plate. At several points these appear to apply pressure to hold the plug wires in place. I can't move the wires without loosening something but I'm not exactly sure what to loosen. Also, is there a recommendation for getting a screwdriver on those screws under the timing plate? My shortest driver is way too tall.
 

Tim Frank

Vice Admiral
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Jul 29, 2008
Messages
5,333
Check the "secret files"....good explanation in there.
Also, it would help if you mentioned a few details about the motor.....HP , model, would be a great start.
 
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htr2133

Seaman
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Jun 2, 2011
Messages
74
Sorry, that was in my signature so I didn't add it to my op. I have a 73 Johnson 6hp Seahorse. I've been all through the secret files and didn't see anything about that, but I will check again.
 

Willyclay

Captain
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Sep 8, 2006
Messages
3,239
I have the same motor and the factory service manual. It is pretty brief in that section but I will copy it here in an effort to try to help you.

"Remove armature link spring clip. Loosen four Phillips head screws attaching magneto armature plate to power head. Lift magneto assembly from power head. All components may be removed from the armature plate by removing the attaching screws. The spark plug high tension leads can be pulled from the coil and lamination assemblies." There are pictures that accompany these instructions which I can scan for you if needed. Let me know.

FYI, the factory technicians used "special tools" to install new coils and to set the points. Forum member F_R can help you with those if you send him a PM.

Good luck!
 

AlTn

Commander
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Mar 9, 2010
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?..the armature plate needs to come off to replace the ignition wires.... remove the 4 phillips head screws closest to the crank and the armature plate will lift off...if the plug wires are held by a clamp attached to a head bolt...remove the head bolt and clamp, unless you can get the wires out of that clamp another way..you should now be able to slide the plug boots and wires by the vertical shaft and have the armature plate with wires removed ...just loosen the clamps on the underside of the plate enough to replace one wire at a time...work with one coil and one wire at a time..it'll lessen any chance of a mix up
 

htr2133

Seaman
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Jun 2, 2011
Messages
74
Thanks guys! I replaced the bottom cylinder condenser and cut of half inch of the old wire and reinstalled the new coil. Got great spark finally. Took it to the lake and it ran better than I ever remember it running! Made me proud.

I am glad you guys posted the info about loosening the armature plate. Next time I have the flywheel off those plug wires are getting replaced.
 
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