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seattleworm

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I had my first power on last night, but got really scared. When I turned on the master, my prop started turning as well. I turned the master off quickly so the prop blade turned no more than 10 degrees or so, nothing is damaged and no one is hurt. But it sure scared me. After checking the wiring around starter relay, I found the diode is to blame. I installed the diode per instruction coming with it, but it is closed (showing about 600 ohm) from master relay to starter relay switch stud, while closed from starter relay to master relay. I am not electrically savvy, but is this just wrong? When it's wired this way, the starter relay is closed as soon as the master is on. Shouldn't the diode be wire the other way? I disconnected the starter relay diode, and all is well.

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IMG_2246.JPG
 
My memory is fuzzy, but from the diagram, it looks as though the diode goes to ground, not the power side of the master relay.
 
You wired the diode wrong on the starter solenoid. It's supposed to go from the ignition switch terminal to *ground*, not to the battery terminal.

The Master Relay protection diode does go between the battery terminal and the switch terminal.
 
As above!

Lesson (which I am sure you know know) is to "build" up the electrics rather than one great "power on". I certainly left the starter motor disconnected until the engine was ready and safe, aircraft outside - but had used a meter to verify there was power there. Ditto expensive avionics ;)
 
Yup, the diagram clearly shows that it connects to ground, which is the mounting lug for the solenoid, NOT one of the big wire terminals.
 
Neal@F14 said:
You wired the diode wrong on the starter solenoid. It's supposed to go from the ignition switch terminal to *ground*, not to the battery terminal.

The Master Relay protection diode does go between the battery terminal and the switch terminal.
Click to expand...

Yes, it's backwards. The second picture you posted shows the big ring terminal going to ground via a mounting bolt.

You have yours going to the positive power terminal - this activated the relay when the master was switched on.

Vans drawings in the second picture are correct.
 
Thanks all!

I feel I am idiot on mis-reading the instruction. Now I see it's connected to the "ground". Yeah, I will have the starter cable disconnected until I am ready for the first engine run. At least I know the starter is working :) Still, so glad no more damage is done. It can be much worse.

Thanks!
 
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Thanks Bill! Great reference for me. I have been searching for something like this, but couldn't find a good one.
 
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