Originally Posted by Ron Stewart
Originally Posted by Jay K
Was the original 3post used the mount for the ground of side of the coil. And the new 4post was isolated and required the extra post to be connected to ground???? Cause that's pretty common....these solenoids are special for airplanes lol
I believe the original 3 post solenoid is internally connected to the 12 volt side of the solenoid and the master switch puts ground to the 3rd post.

Understood. Thanks for the info. And I attached 2 pages of wiring diagram that shows exactly what you describe.

So a new solenoid that has 2 small post possibly requires a jumper wire...assuming the coil isn't internally connected to the battery + post.

[Linked Image from d29y7fsthxbb26.cloudfront.net]
https://www.aircraftspruce.com/catalog/appages/cessnapart71.php
Attachments
c150 battery.start circuit.pdf (54.94 KB, 10 downloads)

Last edited by Jay K; 11/09/24 09:05 AM.
1976 c150m