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-   -   Skytec Starter solenoid jumper wiring (http://www.vansairforce.com/community/showthread.php?t=148784)

Norcalrv7 04-19-2017 10:50 AM

Skytec Starter solenoid jumper wiring
 
I bought a new Skytec Starter from Vans for my 360 -7a. It has been wired via the "experimental" diagram that came with the starter. This uses the solenoid built into the starter,10 Gauge wire, and the main solenoid wire that I have driven through a 30amp automotive type relay.

The main power wire to the starter itself is 6 gauge wire and a 250amp fuse coming from my battery on the firewall.


Skytec's diagram:
http://www.skytecair.com/images/P1/E...iring_1100.jpg

Every other start or so, I must push my starter button 2-3 times to get the starter solenoid to engage. Some basic troubleshooting shows a drop to 9.8 volts or so at the solenoid with it engaged. Surprising to me since #10 wire should be more than adequate for this 20 amp application.

Battery and main connections in the aircraft are well maintained and once the solenoid engages, cranks the engine rapidly.

Before you give me a hard time for not just wiring it like a normal starter, Curious if anybody else has had success with this method.

Caleb

dlloyd3 04-19-2017 01:00 PM

Yes, mine is wired like that. Check the voltage drop at the switch. What switch are you using, is it rated for 30A?
I did have a Skytech solenoid stick when the engine was hot. Replaced it at 150 hours, with a solenoid bought at O'Rielley's and no problem since.

hgerhardt 04-19-2017 07:02 PM

It's probably a sticky solenoid on the starter. I've had 2 now. It's a $20 part. See this: http://www.vansairforce.com/communit...d.php?t=135453

Also, 6 ga seems pretty wimpy for power for a PM starter. 4 ga would be better.

Heinrich

TJCF16 04-19-2017 08:06 PM

I had problem with my sky tech starter staying engaged for about 2 to 3 seconds after releasing the start switch. I removed the jumper wire on starter and ran a wire back to the L terminal on the start solenoid. No more problems. This is the way Vans tells you to wire it. What happens is when you let off the start switch the field slowly collapses which back feeds through the jumper and holds the starter engaged.

Norcalrv7 04-19-2017 11:30 PM

Quote:

Originally Posted by dlloyd3 (Post 1166850)
Yes, mine is wired like that. Check the voltage drop at the switch. What switch are you using, is it rated for 30A?
I did have a Skytech solenoid stick when the engine was hot. Replaced it at 150 hours, with a solenoid bought at O'Rielley's and no problem since.

I am using a 30A Bosch relay to actuate the solenoid. Next step is to trace back to power source and see where I am loosing so much voltage.

Caleb

jakej 04-19-2017 11:57 PM

Starter wiring
 
This link, the latest info from Skytec should answer some questions -- http://www.skytecair.com/Wiring_Diag.htm ;)

rapid_ascent 04-20-2017 07:41 AM

#10 wire with a 20 amp current would have a 20mV (0.02 Volt) voltage drop per foot. So a 3 volt drop would be a 150 foot wire. Sounds like the wire size isn't the problem.

Check the voltage drop across the relay contacts. You might also want to check your battery output voltage directly on the battery when it is under load during starter operation.

bret 04-20-2017 10:18 AM

That first .25 second of start could see 300-400 amps and cause a big voltage drop - loss, I have 2 Ga to the starter.

lr172 04-20-2017 02:06 PM

Quote:

Originally Posted by Norcalrv7 (Post 1166803)
Every other start or so, I must push my starter button 2-3 times to get the starter solenoid to engage. Some basic troubleshooting shows a drop to 9.8 volts or so at the solenoid with it engaged. Surprising to me since #10 wire should be more than adequate for this 20 amp application.

are you reading 9.8V while the solenoid is engaged and the engine is spinning via the starter motor? If so, 9.8V sounds about right. If you disconnected the main batt feed to the starter during this test, measure voltage at the solenoid and the input side of the 30A relay. That might help you narrow down where you are picking up the resistance problem. I would speculate that there is a problem with the winding in the solenoid that is providing incorrect resistance that is drawing too much power as well as not providing the proper magnetic field to move the plunger / contacts.

if you were getting 9.8V with the engine spinning, you're looking for the plunger / contacts hanging up inside the solenoid, due liekely to improper clean up of surfaces during installation if new or pitting contact surfaces if old.

Larry

Norcalrv7 04-21-2017 10:57 AM

Quote:

Originally Posted by lr172 (Post 1167126)
are you reading 9.8V while the solenoid is engaged and the engine is spinning via the starter motor? If so, 9.8V sounds about right. If you disconnected the main batt feed to the starter during this test, measure voltage at the solenoid and the input side of the 30A relay. That might help you narrow down where you are picking up the resistance problem. I would speculate that there is a problem with the winding in the solenoid that is providing incorrect resistance that is drawing too much power as well as not providing the proper magnetic field to move the plunger / contacts.

if you were getting 9.8V with the engine spinning, you're looking for the plunger / contacts hanging up inside the solenoid, due liekely to improper clean up of surfaces during installation if new or pitting contact surfaces if old.

Larry

Larry, thanks for the feedback! This is exactly what I did. The solenoid and relay used to be wired with #14 wire but were replaced with #10. the problem still persists to the same extent even know the voltage went up under load by about half a volt after the wire size change.

I think I'll swap out the solenoid today, I heard a Ford Crown Vic solenoid fits

Caleb


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