Skipping the starter solenoid

If the starter has a built-in solenoid, all you 'really' need is a pushbutton/key starter switch - However - there is still a significant current that flows through the starter switch (see: http://www.aeroelectric.com/articles/strtctr.pdf), so Bob Nuckolls still shows a starter solenoid between the switch and the starter in his diagrams. There have been discussions about this on the AeroElectric Matronics list if you want to do some searching.

I plan to use a Bosch relay, rated for 40 amps, instead of a solenoid between my starter switch and the starter solenoid (lighter, cheaper).

Dennis Glaeser
7A
 
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The primary reason for NOT bypassing a starter solenoid and using the solenoid mounted on the starter is with this method the cable running to the starter is always "hot". With all the vibration under the cowling, it is not at all unusual for these heavy cables to break. If this happens you will have a "hot" heavy duty cable running loose under the cowl. Even if the cable is strain relieved, it is still in very close proximity to the grounded starter case. This can wipe out the electrical system very quickly and/or start a fire. Neither of these situations is good.
Mel...DAR