Re: Engine still won't start

[jlandry@domain.elided (John A. Landry)]

At a recent NATO press briefing, Roger Scow <rscow@domain.elided> was heard
threatening Yugoslav President Slobodan Milosevic...

>Well, I'm still having a heck of a time getting this 392 to start.  Here's
>where I am:
[snip]

Roger,

Did you by chance try using starter fluid?  Just on the chance there's
something wrong with the carb, this might help at least get it to kick off.

Does it turn over fast (normal)?

The reason I ask is that I had a similar problem with my 1984 V65 Magna
motorcycle.  I tried for a month to start this damn thing after winter
hibernation.  I went through the same things as you with your 392... verified
fuel, spark, etc.  There's no distributor (fully electronic ignition) but all
shop manual testing showed everything was perfect.  I even resorted to using a
large deep cycle / marine starting battery via jumper cables after I toasted
the small motorcycle battery from the cranking.  I knew I was getting fuel
because I succeeded in repeatedly flooding it (raw fuel on the spark plugs).
Some level of spark was present on the plugs when removed and the engine
cranked.  I'd occasionally get a loud backfire out the exhaust just after
releasing the starter button.

What it turned out to be was this: The starter had worn internally to the
point that it was probably drawing over 80 amps as soon as the starter button
was pressed.  The amperage would then drop off to maybe 40 amps during
continuous cranking.  This high amp draw in the electrical system left about 6
volts to power the electronic ignition, which was not enough as it required
between 7 and 9 volts minimum on this system to operate properly.  This was
not enough to provide the level of spark needed to ignite the high compression
air fuel mixture of this motorcycle.  I believe the backfire was the result of
the ignition system momentarily having adequate voltage immediately after the
starter was de-energized and the engine was still rotating to a stop.  The
ignition would thus spark one time and ignite the fuel saturated exhaust
system.

On this basis I did a simple refurbishing of the starter by cleaning up the
commutator on my lathe, cleaning, lubricating and reassembling.  The brushes
had plenty of life left on them so I decided not to replace them yet.  The
cummutator was worn in a strange wavy pattern, not unlike a roller coaster.
After the starter was reinstalled, the engine cranking speed was down right
wicked!  The bike fired up instantly the first time I cranked tried it.  With
a fresh starter, the amp load starts at about 40 settling down to about 20
amps during continues cranking.

Could it be possible your starter is drawing so much amperage that your
Prestolite just can't produce a spark hot enough?  At least I would measure
the voltage present at the positive (+) side of the coil *during cranking* to
see what you have.  If you have something less than 9 volts, I'll bet that's
trouble.

That's all I can think of at the moment... trying starter fluid and checking
the voltage available for the Prestolite.  If the voltage thing checks out OK,
you might see if you can borrow a different IH distributor (points if
possible) to see if the Prestolite is somehow at fault.

Good luck,

John L.
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