Old 18 hp Johnson Seahorse Wont Start

[tedbbear59]

model number fde-12<br />I believe it is a 1958 with an electric start . .If i remove the plugs and hold them away from the block it jumps a good spark but if i ground the plugs to the block there is no spark between the electrode and the tip ...Also there are two wires coming from under the flywheel that have been cut and taped. Are these kill switch wires or are they for lights and etc .Does this model have a charging system of any kind. Any info will be a great help .<br />Thanks Bear

 

[steelespike]

Re: Old 18 hp Johnson Seahorse Wont Start

If the motor had a charge circuit there would be a seperate generator with a belt.I don't think a generator was available.Most likely the wires are for the kill switch.<br /> I don't understand how spark could jump without grounding the plug.Something strange is going on.<br /> The only thing I can think of is some sort of strange corrosion in the plug boot/wire that allows the spark to jump ungrounded but when you ground it goes directly to ground.Check all wires especially under the flywheel and the plug wires and boots.

 

[CFronzek]

Re: Old 18 hp Johnson Seahorse Wont Start

I've heard it's possible for a spark plug to develope a carbon path down it's side that will let the juice discharge to ground without jumping the electrodes. But, in 50 years a I have never seen a case of this. Usually, if the plug wouldn't fire the juice found a way to ground thru' the insulation on the plug wire. <br /><br />Charlie