Help with an Onan CCK engine

[TimWafer]

Trying to help a friend get an old Bobcat skid steer running he recently acquired. It has an Onan CCK-MS/2866J engine. It has no spark at all and has obviously been screwed around with by clueless hoards in the past so no idea if any of the wiring is correct.
It has a 12V battery and a Onan 166C346 coil. the coil is stamped 6 volt but is wired to 12V. I do not see any positive or negative indications on the primary connections of the coil at all. i get about 1.3 ohms across the primary terminals. The secondary terminals have about 12,400 ohms between them. There is a resistor connected between one primary terminal and the points. Is this correct or should it be on the other terminal to drop the 12v down to 6v? I think this is one of the systems where both plugs fire at the same time only one is wasted on the exhaust stroke. Any help is appreciated. Im also clueless when it comes to this thing.
Tim

 

[DanielW]

I believe the resistor should be on the other side, but I can't remember for sure. You can probably find the electrical schematic and service/parts manuals at this link (see below): Some helpful chap uploaded a huge pile of Onan manuals there. Go to that link and search for CCK - you'll find a lot of stuff. Link to Onan manuals: https://www.skilledcrafting.com/onanfiles/

I'd be surprised if it's the coil, or if it was left wired up such that it didn't run at all. First place I'd look would be cleaning the contact surfaces of the points; a little bit of oxidation on them is a pretty common cause of no spark on old engines. The good thing is that the electrical components of those old Onans are pretty much indestructible; I'd be very surprised if you end up having to replace any components.

You're probably best to ask this question on the Smokstak forums/website: Lots of Onan experts over there.

 

[DanielW]

Hmm, just re-thinking my last reply. I think the resistor on yours is actually in the correct place. This is for a slightly older series, but I suspect it applies to yours too. Note resistor between coil and points:

 

[Fritz Maurer]

First of all, you have to have a dual coil. Can't fire two plugs with one coil. A red flag went up for me when you started talking about six volt. Never heard of any CCK being 6 volt.

This is a simple system, don't complicate it by looking at the whole wiring diagram , the flywheel alternator has zero to do with the ignition system other than a voltage tap; Just think, batt to coil, coil to points , high tension leads to plugs. The points are right on top of the block. The above wiring will get you spark if the components are functional. You keep the charging circuit separate and worry about that later.

But you HAVE TO HAVE a dual coil before any of it will work.

 

[zuhnc]

6 volt coils are common on Onan products. I have been working on Onans since the mid 80's. The resistor can be on either side of the coil; the electrons don't care. Drops 6 volts across the resistor, so the coil sees the proper voltage. And, Onan uses a dual-terminal coil, as well (as does Harley-Davidson). Both plugs fire at the same time, one on the exhaust stroke, the other on the compression stroke. To test, BOTH plugs have to be grounded.

No spark is generally caused by corroded points or failed condenser (capacitor). Modern parts from "the land of almost right" are highly suspect. Even the auto parts stores, selling various brands, have a hard time getting good parts from anyone.

There is another forum (SmokStak) that has Onan gurus "in attendence". They can answer any question you have about this engine.

Go here - http://onan.xmsi.net/, or go here - http://www.skilledcrafting.com/onanfiles/, and do a search for your engine model number. That will get you the proper manuals for your engine. Don't forget that the specification number is the very last letter of the complete model number; that would be "J" in your case. zuhnc

 

[DanielW]

First of all, you have to have a dual coil. Can't fire two plugs with one coil. A red flag went up for me when you started talking about six volt. Never heard of any CCK being 6 volt.

This is a simple system, don't complicate it by looking at the whole wiring diagram , the flywheel alternator has zero to do with the ignition system other than a voltage tap; Just think, batt to coil, coil to points , high tension leads to plugs. The points are right on top of the block. The above wiring will get you spark if the components are functional. You keep the charging circuit separate and worry about that later.

But you HAVE TO HAVE a dual coil before any of it will work.

The part number the OP has for the coil is for a dual-terminal coil, and the correct one for that CCK. Sounds like the OP has everything they need, and probably in the correct orientation too. A little points and plug clean-up and ensuring both plugs are grounded and have the coil leads connected when checking spark would be my first checks.

 

[JOCCO]

If it's a cck should have a square box on top by carburetor. That is your points, condenser. There were a couple different ignition systems used.

 

[TimWafer]

First of all, you have to have a dual coil. Can't fire two plugs with one coil. A red flag went up for me when you started talking about six volt. Never heard of any CCK being 6 volt.

This is a simple system, don't complicate it by looking at the whole wiring diagram , the flywheel alternator has zero to do with the ignition system other than a voltage tap; Just think, batt to coil, coil to points , high tension leads to plugs. The points are right on top of the block. The above wiring will get you spark if the components are functional. You keep the charging circuit separate and worry about that later.

But you HAVE TO HAVE a dual coil before any of it will work.

Let me clarify that the coil IS set up for dual plugs. It is an original Onan coil marked 166C346 and clearly says 6 volts on it. I have cleaned the points numerous times with an emery board to no avail so far. That was my first step. The CCK manual i found says the resistance between the primary coil connections should be between 3.87 and 4.73 ohms. I get about 1.6 ohms. Thats why i was questioning the coil and the resistor connected to it. I am trying to diagnose the problem , rather than just trowing parts at it. Ive seen other data online that suggest other resistance values for it so not sure if its alright or not. I think this machine has been though several auctions and each new owner has played with it, trying to get spark. I dont trust anything on it as being correct at this point. I made up a couple new plug wires as the looked suspect but have yet to try it again.

 

[DanielW]

Let me clarify that the coil IS set up for dual plugs. It is an original Onan coil marked 166C346 and clearly says 6 volts on it. I have cleaned the points numerous times with an emery board to no avail so far. That was my first step. The CCK manual i found says the resistance between the primary coil connections should be between 3.87 and 4.73 ohms. I get about 1.6 ohms. Thats why i was questioning the coil and the resistor connected to it. I am trying to diagnose the problem , rather than just trowing parts at it. Ive seen other data online that suggest other resistance values for it so not sure if its alright or not. I think this machine has been though several auctions and each new owner has played with it, trying to get spark. I dont trust anything on it as being correct at this point. I made up a couple new plug wires as the looked suspect but have yet to try it again.

Though I don't know for sure, I suspect Onan did what loads of other manufacturers did at different time: using 6V coils in 12V applications, and just adding a resistor in-line with the primary to bring the combined resistance up to 3-4 ohms. Check the resistance of the coil and resistor in series; I'll bet it's about what the manual says it should be.