On Tue, 06 May 2008 09:10:55 -0400, jeff wrote:

However, if your devices are unregulated
that could put out a lot more - 18 Volts or more. Still, I don't wee
where the problem might be so I'll be very interested in hearing abotu
the eventual solution.

That's the only explanation that makes sense to me: If the engine has
electronic controls they may be interpreting an over voltage condition
as an error, or perhaps an over voltage causes the controls to
malfunction in some way.