[Bob Putnam]

Chris,

The tach:

With the engine running, check the voltage at the MSD tach output after disconnecting the wire from the tach. It should be roughly 1.5V.

If that reads closely, try an external tach on the output.

If that's OK, check the back of the SW tach. Doug tells me that some versions have a cylinder selector on the back. Make sure that the the arrow isn't in between numbers.

If all else (doesn't) fail, we'll replace the tach.

Now for the Ugly Part:

This is the first leaking heater that I've heard of. We'll replace it, of course. Give Peter or Bryan a call for details.