I suspected I'd blown my regulator using the battery switch while running - no tacho, volts at battery the same whether engine running or not. The Seloc manual has a static resistance test.<br /><br />Did the static test after a fashion - I don't have thick and thin red wires. The tach resistance was completely wrong, as was the resistance of a stator input to ground. A new one will be needed. A supplier in the US quoted me for a CDI regulator with a different part No. (also more expensive at $120 + $9 P&P). Is it a direct replacement? I await his reply.<br /><br />Still never found the Mercury part No.<br /><br />1995 115 Hp 4 cyl Mercury OG198241