Seeing 5V from Ignition Switch?

1984 Ski Nautique 2001
Engine Model PRD WR R10
Pleasurecraft Marine
Right-Hand Rotation from Rear
351 CID
Warner Velvet Drive Model 10-17-003
Direct Drive (1:1)
Mallory YLM554DV Distributor Conversion


I'm kind of stumped at the moment.

Here is the engine wiring diagram from the PCM Engine Owners Manual:





When the key is set to Off or to Run (engine not running), I have 13.5V at the big red cable on the starter relay/solenoid, and 13.5V at the orange cable on the alternator.

When the key is turned to Start, the engine turns over (won't start due to issues below).

When the key is set to Run, I have low voltage (5V or less) at the choke, at the ballast resistor, and at the coil + post.

Per the diagram, the ignition switch gets full voltage from the red wire from the solenoid, and when set to Run should send full voltage via the purple wire to the choke and ballast resistor. How am I getting 5V on this line?

My son is at football practice, so I may have to fold my big old butt under the dash to measure the voltages at the switch. Or maybe have my daughter get under there. My son removed each connection at the ignition switch, cleaned it and reconnected everything tight. I wonder if he's got something touching, shorting out the full voltage down to 5V. Anyone seen something like that before? I checked the fuse, and it's good.

Any thoughts would be appreciated.

check that you have 12v going through the switch.   I don't know the terminal labels, but you shoudl be able to search for them.   if y ou have 12 going in, and only 5 coming out, your switch is bad.   It doesn't happen too often that the switch is bad, but it does occasionally.   A 7 volt drop is resistance. if it was a direct short, you'd blow the fuse. Check your connections etc too. good clean connections and wires make for a happy electrical system.

Dan in CT> "Good luck, I assume if you have a big old butt, as do I, you probably have the same sausage fingers. Much better at eating doughnuts than working under the freakin' dash.

Yup! lol


Dreaming> "A 7 volt drop is resistance. if it was a direct short, you'd blow the fuse."

That is an excellent point.


8122pbrainard> "Ohm out the switch between the B and I terminals and see what you get."

Another excellent suggestion.

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Dan in CT> "Last thing, check the wiring harness plug."
Dreaming> "Check your connections etc too."
8122pbrainard> "Also, check all connections and harness plugs/receptacles for corrosion."


Ding ding ding ding.... Winner! (partially, at least)


This has been a tough one. It turned out to be three separate issues, plus a fourth issue, and we were chasing our tails 'round and 'round.

First, the ignition switch tested good, and showed full voltage on the ignition connection with the key set to Run.


Issue #1: My freakin multimeter was bad. Dammit! This was the second digital meter that has given me very incorrect readings. It wasn't a Harbor Freight cheapie; I think I paid 40 or 50 bucks for it a few years back. I checked it on the AC house wiring and on the battery in my truck and the readings were sometimes right, sometimes wrong. It's in the garbage now. Last night, I went and bought an analog meter--I missed watching the needle swing on the old meter I had ten years ago, so now I'm back to a swinging needle. Anyway, I don't think the 5V was really 5V. I'll measure it tomorrow after it stops raining, hopefully. But it was well below full voltage.


Issue #2: The wiring harness plus had two intermittently bad connections. With the key to Run, I see full voltage at the choke, at the ballast resistor, and at the coil + post. If I would wiggle the harness plug a bit, the voltage would cut out and in. My son and I checked this out for quite awhile... it was not in the wiring, but right in the plug. I had already cleaned the pug thoroughly (contact cleaner, wire brush, pipe cleaners), and it wasn't a cleanliness issue--moving the plug was breaking the connection momentarily on the red and purple wires. The posts fit tightly enough into the corresponding barrels; I think the wire connection to the copper in the plug half away from the engine were going bad. I decided that I'm not going to splice a new plug into 8 wires at this point (at the time of the eventual stringer job, all new wiring will go in), so I bypassed the plug for those two wires. That solved the voltage cutting out. I also taped the harness plug together and used more zip ties to stabilize the whole wiring harness back there.


Issue #3: OK, I do NOT understand this one. The Mallory electronic ignition conversion is pulling the voltage down when the key is on Run. I need to explain a bit... The PO had a mechanic install the Mallory unit. He ran the red wire from the Mallory dizzy to the electric choke, and slipped a flat spade lug alongside the choke spade lub, then seated the ignition feed wire clip over the two flat lugs. The dizzy lug would wiggle inside the clip, and I hated the set-up. So I had pulled the dizzy red wire lug off, planning to splice it into an ignition wire instead. That's when I was getting the full voltage readings at the choke, at the ballast resistor, and at the coil + post. I have the dizzy feed spliced in now. With the Mallory back in the circuit, the voltage is pulled down with the key on Run (engine not running), but the engine will run fine. I will get the true voltage readings in a day or so, with the new multimeter once the rain dries up. I am able to duplicate the behavior by detaching and attaching the small 3-connector plug in the Mallory wiring (engine off).


Issue #4: The ballast resistor is either fried or the PO put in the wrong one. It measures 0.1 ohms and doesn't drop the voltage to the coil at all. This probably led to problems with the Accel ignition coil the PO had installed (I've replaced it with an MSD Blaster2 coil). NAPA is getting me a 0.85 ohm resistor tomorrow. There was an old ballast resistor mounted near the current one, which wasn't being used. I had pulled it off a while ago. Oddly it measure 50 ohms, so either it's ruined or was also the wrong one.


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Question A: With the key on Run and the engine not running, should the Mallory unit pull the voltage down on the (pre-resistor) ignition feed it's attached to? I may have to contact Mallory about this.

Question B: When a ballast resistor "goes", does it's resistance typically drop to 0, or rise to a high ohm reading?

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Thanks for all your help. I am going to be *ecstatic* when these wiring issues are resolved.

Steve