Spark issue (fixed!)

[Johnny340]

My 61x runs fantastic for the first 30 minutes and then sometimes it doesn't fire on the rear cylinder. It's sounds like a turd and wouldn't pull the skin off a bowl of custard. I take in, eat lunch, go back out and it's fine for another half and hour or so.
Is this a coil going bad? (FYI, I have a Pro-Tec modded CDI.)
What should I try? Many thanks!

 

[cmeripper26]

You can pull the plug boots off and trim the coil wire insulation back a bit then re-attach the boots.

 

[Johnny340]

You can pull the plug boots off and trim the coil wire insulation back a bit then re-attach the boots.

Thanks for the input. I was planning to try that actually but then wondered how those connections could be fine for a while and then suddenly cause problems. It wouldn't hurt, I suppose, so I'll do it.

Any other thoughts? Anything that could get worse with prolonged operation/heat?

 

[cmeripper26]

You'll notice when you pull the boots off that there is not much wire exposed that makes contact with the boot. This bit of wire after time can be burnt up to almost nothing depending on how long those coil wires have been run in your ski. This is an easy place to start troubleshooting

 

[Johnny340]

You'll notice when you pull the boots off that there is not much wire exposed that makes contact with the boot. This bit of wire after time can be burnt up to almost nothing depending on how long those coil wires have been run in your ski. This is an easy place to start troubleshooting

I put on some MSD plug boots on and will give that a try. When I went to strip the rubber casing from the wire, the strands broke about an inch further up from where I was stripping from so most of them must have been damaged.

 

[cmeripper26]

Just be careful of the MSD boots and those wire crimps... you need to make a real good contact with those wire crimps that insert into the MSD boots with the plug wires. I recomend the NGK boots.

 

[Johnny340]

OK, so this problem is still haunting me. I got a new coil and new MSD boots. I get a steady 4.18 K ohms on this new coil.
Today it ran great for about an hour and then suddenly the rear cylinder wouldn't fire under load. If I can slowly get to speed it will rip on both.
See pic below of brand new plugs. The rear one is black after not firing.
I took the reeds out and they are toast - especially the front ones. I have new Carbon Tech's on order. I'm sure this will help the overall performance but I don't think it entirely explains only running on one cylinder.
Any thoughts here are much appreciated! Thanks.

 

[cmeripper26]

How old were those reeds? What happened to cause that on both reeds. Did you chew something up?

 

[Johnny340]

How old were those reeds? What happened to cause that on both reeds. Did you chew something up?

I don't know how old because I recently bought the ski and was told they were new. I haven't put much time on it either. I think they just get old and fray. They work better than stock but for a shorter life span.

What about my 701 'single'? Any ideas? The front reeds were worse but that plug fired whatever was sent to that hole. Could a bad CDI affect only one cylinder?? Actually, that doesn't make sense to me because whenever the coil is told to 'go' is energizes both plugs simultaneously doesn't it? This is pissing me off now...

 

[cmeripper26]

Have you checked for spark on both plugs or compression on each cylinder?

 

[Johnny340]

Have you checked for spark on both plugs or compression on each cylinder?

Yes, that's all good. I tested the stator and it was within spec. When I tested the CDI I got totally different ohm readings than what the manual says. It's a Pro-Tec modded 6M6 CDI so I don't know if the specs for it are different than the 61X.

 

[cmeripper26]

When the power wire of the CDI (Red) is unhooked did you test the wire for a 12 volt reading. I use the neg. battery terminal as the ground then check the CDI power wire for a reading and let me know what you get. Should get a full 12

 

[Johnny340]

When the power wire of the CDI (Red) is unhooked did you test the wire for a 12 volt reading. I use the neg. battery terminal as the ground then check the CDI power wire for a reading and let me know what you get. Should get a full 12

Thanks for the replies.
I don't have a red power wire going to the CDI directly. I have a red wire that goes to the regulator and start switch that reads 12.49V.

 

[cmeripper26]

Sorry, whichever wire is the power from your CDI is the one you check for a 12 Volt reading. I run an Advent setup, the power wire from that CDI is the Red Wire. If you unhook the power wire and use your volt meter it should read 12 volts. Did you Ohm out the coil wires. If you have a manual it should tell you waht the resistance reading should be. And i forgot to ask, are both cylinders getting fuel?

 

[Johnny340]

I know....every CDI I've seen has a Red power wire, except this one. I can't figure out which one is the power wire either. None have 12V to it. Do you remember what your Red wire off the Advent connected to?
The coil is brand new and tests within spec: .8 ohms on Orange and Black. 4.18 K ohms at the plug boots.
Both cylinders are getting fuel.
I have an Advent CDI that is arriving tomorrow with the new reeds. I hate to make a bunch of changes at once but I can't put those reeds back in the way they are. If I change reeds & CDI and it runs properly, I'll have to assume this CDI was bad.

 

[cmeripper26]

The power wire for Advent and most CDI's is split from the Fuse coming off the relay to the S/S harness.

 

[Johnny340]

OK, I'm still stumped over this. Occasionally it runs perfect for 15-30 minutes and then major bog and no power. Runs on one cylinder only when it's bogging. Seems electrical because of the fact that there is no spark on one cylinder (sometimes front and sometimes rear!).
So far I have changed the plugs BR8ES (ADA head.)
Changed MSD boots
Changed Coil WSM
Changed CDI (Advent)
Changed Stator
Cleaned carb and changed internal filter.
Changed in-line filter
Changed Reeds
Pulled head - No scoring, good O-rings, everything turns free by hand.

I've been searching and can't find anything exactly like this. Could it be a bad ground? Cracked pipe? But when it runs, it runs great... It's an intermittent problem.
Thanks for any help on this frustrating gremlin.

 

[Buckwild12]

I am by no means a guru on this, but i was told to use the b8es plugs with an ada hea

I was told the br8es plugs will mess up your coil, no real idea if that is the case but.....

 

[Johnny340]

I was told the br8es plugs will mess up your coil, no real idea if that is the case but.....

The ES plugs have the correct reach for the ADA head. I run the resistor type (R) because you must with an Advent T3 ignition according to them.

Anybody have any other thoughts about this or anything else?

Also, I already tried disconnecting the Stop switch and it made no difference.

 

[cmeripper26]

I was informed that sometimes Advent igintions may be faulty causing them to run intermittently right from the factory. However i would test the coil first and then switch to an NGK screw on type boot, this way you know you are getting good solid contact. Good luck, let me know. Also test the power wire on your Advent now that you have that one hooked up! Let me know.