Momentary Engine "Cut-out" at Speed

1984 Ski Nautique 2001
Engine Model PRD WR R10
Pleasurecraft Marine
Right-Hand Rotation from Rear
351 CID -- 255 h.p.
Warner Velvet Drive Model 10-17-003
Direct Drive (1:1)
Mallory YLM554DV Distributor Conversion



This might be related to the transmission neutral safety switch issue I'm having (but probably not, as this is in forward gear).

Every once in awhile, when at speed (for example, maybe 2500 or 3000 rpm), the engine "cuts out" momentarily--for a very short period of time, like a small fraction of a second, but it is definitely noticeable.

Usually, it happens once and that's it.

On the last time on the lake for our vacation, it happened twice in succession to my daughter while pulling a wakeboarder, as a result she started to throttle back and the engine died. I towed them to the dock. It turned over but wouldn't fire. We were getting ready to leave so I haven't looked at it yet.

The previous owner installed a Mallory YLM554DV Distributor Conversion. I found the installation instructions on the Mallory website and will trace all the wiring to see if it's right. My other boat (Mercruiser I/O) has a Pertronix conversion and I used to have a problem with the resistor wire heating up and reducing the voltage to the Pertronix which would then shut itself down (bypassed the resistor wire in the harness and went to a regular ballast resistor).

I'll also check the fuel pump, but this cut out thing is electrical. It reminds me of the reverse cut out on my Mercruiser stern drive.

Any thoughts?

Thanks.

Steve

Chris,

> Why don't you temporarily bypass the NSS to see if the problem goes away? Don't leave it that way though . . .

The boat is mostly being used by teenagers, captained by my son and daughter, to wakeboard and slalom. I have strict rules about the engine being off when near someone in the water. They also have it drilled into their heads that the neutral warm-up button must be pulled out for all starts, but even then, I do not want the boat to start in gear with anyone in the water. The cut-out problem is pretty intermittent (maybe 5 times in 6 days) so I'm not comfortable having the safety switch bypassed.


> Really sounds like the ignition system itself to me.

I know... and not my strong suit. As much as I hate messing with points, I had mixed feeling about the Mallory conversion. It took me the better part of a whole season to get the Pertronix on my Mercruiser to behave.

Steve

Sorry for the unsafe suggestion, I was thinking only for a test run, not for a whole day.

Didn't need to remove the seats. With the observer seat leaned aft, my son can just lay on the floor and work under there. He removed and cleaned all ignition switch connections, all clean and tight now. Also all fuse holder connections. We'll see what happens when we get her out again.

Man, I sure wish that panel could flip for working in there. It would mean longer wires and tubes, but it sure would be nice.

We also traced all the wires from the Mallory electronic ignition conversion. Everything seems to be hooked up correctly, per the Mallory installation manual.