If I have a wiring error, I simply can't find it...UPDATE: FIXED!

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NJ-boatbuilder57
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Re: If I have a wiring error, I simply can't find it...

Postby NJ-boatbuilder57 » Mon Feb 12, 2018 10:51 pm

Yes, I added a second wire.

The engine is a bit of a Frankenstein......'59 Gale meets '57 Javelin. I received one of each, neither working, but enough pieces & parts to build one good engine. While there are some small differences, they're really quite identical. When finished, the physical appearance will be a '57 Javelin but the nameplate says Gale. Like I said: Frankenstein.

But let's not get lost in the weeds, either.....there's no reason whatsoever that a '57 Javelin (or *any* 2 cylinder engine for that matter) can't have a kill switch just like the one in the posted schematic. So I've run a dedicated wire from the top points to the kill switch. On the bottom cylinder, it's just a takeoff lead from the vacuum switch to the kill switch. Again, just like the schematic. Ignore all else, electric start, choke, etc.; it's just a points-to-points kill switch like most other OMC engines. Except mine only kills one side.

Tomorrow night I'll pull the flywheel (again) and take more measurements.....

EDIT: OK...sizeable update. While I certainly don't have this figured out yet, the issue is NOT on the magneto plate. I just went out to the shop and disconnected both kill wires from everything else and tied them together....neither wire sparked when i turned over the engine (as is to be expected). So whatever is going on is from the end of those wires, forward, not 'back' towards the points, caps & coils. If nothing else, it looks like I don't need to pull the flywheel! Yay!

Oh, and BU got crushed by Northeastern, 5-2. Not a good night for us hockey fans....

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Garry in Tampa
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Re: If I have a wiring error, I simply can't find it...

Postby Garry in Tampa » Mon Feb 12, 2018 11:46 pm

I think the answer is where you tapped into the vacuum switch. Make sure it is the same post as the one that the breaker point set goes to . . . :)

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FrankR
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Re: If I have a wiring error, I simply can't find it...

Postby FrankR » Tue Feb 13, 2018 7:10 am

Quote: EDIT: OK...sizeable update. While I certainly don't have this figured out yet, the issue is NOT on the magneto plate. I just went out to the shop and disconnected both kill wires from everything else and tied them together....neither wire sparked when i turned over the engine (as is to be expected). So whatever is going on is from the end of those wires, forward, not 'back' towards the points, caps & coils. If nothing else, it looks like I don't need to pull the flywheel! Yay!

Good, now we're finally getting somewhere (I hope)

fleetwin
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Re: If I have a wiring error, I simply can't find it...

Postby fleetwin » Tue Feb 13, 2018 9:13 am

Joining in on this late, and don't want to add any more confusion or time wasted replying to questions/points that have already been discussed.
Nonetheless, like NJBB latest test...So, there is something wrong with harness/boat wiring.
I am looking at the posted wiring diagram, but it sounds like you have made up your own wiring harness and have some other type of stop switch rather than the conventional key switch which just ties the two mag leads together without adding an auxiliary ground...
Let me know if I am incorrect....Don

crosbyman
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Re: If I have a wiring error, I simply can't find it...

Postby crosbyman » Tue Feb 13, 2018 9:44 am

humm.... like I suggested.. if I read this correctly.... no plugs fire when both kill wires shorted towards the engine side... this is good :-)


disconnect kill wires and measure resistance back to the kill switch... is it 0 ohms in kill mode ??

now a second test........ measure individual wires to the kill switch with.....reference to ground

measure each wire with ground in kill mode and run mode ...

I suspect one wire may be getting grounded in kill mode without the two wires being linked together inside the switch during kill mode
this condition if it exists... would kill one set of points leaving the second one running

jmho

NJ-boatbuilder57
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Re: If I have a wiring error, I simply can't find it...

Postby NJ-boatbuilder57 » Tue Feb 13, 2018 1:31 pm

Crosbyman,

That's my exact script for my next round of testing. Not sure I can do it tonight, though.....looks like I have to work.

And: yes.....it's a custom harness, but nothing exotic. Male Deutsch connector on a 2-foot whip coming out of the engine, mating to a Female Deutsch at the transom on a harness that runs up to the boat's dash. I also made a "test box" for my engine stand....Female Deutsch connector with a 2-foot whip going to a 1900 box with individual switches in it. That's the switchbox I'm presently using.

All connectors, cables, switches, etc. have been "rung out" with my Fluke DMM several times now. Nothing looks to be wired "wrong".....and all other functions (starter, nav lights, choke) operate perfectly.

fleetwin
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Re: If I have a wiring error, I simply can't find it...

Postby fleetwin » Tue Feb 13, 2018 3:00 pm

OK, well what are you using for a key switch, or stop switch? There are several types of stop/kill switches available, some use an external ground while others do not. Shutting off your engine is accomplished by connecting the two primary circuits together, not by adding an auxiliary ground to shut the engine off. So, using some stop/kill switches that rely on an auxiliary ground might explain why just one cylinder is losing spark when the key/stop/kill switch is turned "off".
It is also important to mention that all engine functions be wired separately from boat wiring such as lights/bilge pump. Wiring lights/accessories into one of the "m" terminals on the key switch is a big mistake because a coil primary winding is being used for an accessory ground, which usually melts the winding.
You have already determined that the engine shuts off when the two primary leads coming out from under the mag plate are connected together, spark is killed on both cylinders. But, the crazy vacuum cut out circuit is plumbed into the stop circuit, and there are many versions of this system used. So, it is surely possible that your harness/boat wiring set up is fine, but there is a problem with vacuum cut out system wiring. So, I guess I would want to perform another test like the one you just did, but include the vacuum switch wiring in the circuit. The thing that confuses me is that just one cylinder is losing spark when the key/stop switch is turned off, so one primary circuit is finding a ground somewhere, perhaps through the vacuum cut out circuit.
Again, your harness/boat wiring might be perfectly fine, kind of hard to pass judgement on something we can not see.
Needless to say, you may have already explored these areas, I just joined this discussion and surely don't want to add confusion.

crosbyman
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Re: If I have a wiring error, I simply can't find it...

Postby crosbyman » Tue Feb 13, 2018 4:04 pm

fleetwin... he indicated the kill function works fine with 2 wires shorted including vacum cut-off, mercury etc...

the issue creeps in when the switch is involved hence my request to find out what is happening switch side wire to wire ohms

individual wires to ground ohms.......in kill mode and run mode ohms readings

fleetwin
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Re: If I have a wiring error, I simply can't find it...

Postby fleetwin » Tue Feb 13, 2018 5:20 pm

crosbyman wrote:fleetwin... he indicated the kill function works fine with 2 wires shorted including vacum cut-off, mercury etc...

the issue creeps in when the switch is involved hence my request to find out what is happening switch side wire to wire ohms

individual wires to ground ohms.......in kill mode and run mode ohms readings


OK, well this is where I'm confused and need clarification for sure. It sounded to me like he disconnected the two knife connectors from the leads coming out from under the mag plate, then connected them to each other. If this is the case, then the vacuum switch and wiring were not in the circuit when he connected the stop leads together....

NJ-boatbuilder57
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Re: If I have a wiring error, I simply can't find it...

Postby NJ-boatbuilder57 » Tue Feb 13, 2018 7:27 pm

Yes, that's correct. That said, there are no knife connectors. There's modern insulated spade connectors, instead. This engine was a basket case, and is being restored, but with modern electrical components. But whether they're old-style connectors or modern, the concept remains the same: connecting the magneto kill wires to each other kills spark....as it should. And, correct: during that test, the vacuum switch was out of the circuit.

But extend those same wires to a remote kill switch (with the vacuum switch in the circuit, properly wired) and only the bottom spark dies.

I'll try to do more testing tonight.


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