Tachometer causes non start

[john derbyshire <jderbyshire@maxon-hq.co.uk>]

Hi everyone

Whilst we are talking about tachometers.

The tachometer I have in my 1500 spitfire, cause the engine to fail to
start, i.e. it turns over but will not fire.

Fine I hear you say, its gone short circuit and bring the LT down.

But

If I connect it up whilst the engines running, it works fine, and so dies
the engine.

Any ideas ?