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Skytec Starter Issues

RedRaider94

Active Member
I have an IO-360 in my 7 and have had intermittent starting issues that have become worse over time. Pressing the start button, nothing happens the first time (no clunk, no sound of anything). Click it again and I might get half a turn. Press it again and sometimes nothing and then press it again and it turns over (not extremely well) and it starts. It's not to the point where I am not confident it will start the next time.

It has a Skytec lightweght starter. I have replaced the battery, the starter contractor on the firewall (cylindrical black one with 4 terminals coming out), and starter solenoid on the starter itself.

This never used to happen and the plane has 1700 hours on it so something that was working perfect is no longer working and I cant figure it out.

Is the only other culprit the starter itself (may be the original starter) or is there any other place to look? I have no other electrical issues - everything works perfect. If starter, which one replaces the skytec lightweight starter on these engines?

Thanks as I am just completely out of ideas.

Shawn
 
Voltage and connections?

Shawn,

Looks like you hit all the big points (relay, solenoid...). Before you replace the starter you may want to check a couple of more items:

What's the voltage measure at all points along the system before, and during the start sequence?

How does the wiring & terminations look, especially the ground straps at the engine case and firewall, battery -- corrosion/bad crimps/loose wires?

How about the start button itself, contacts in good shape? Also, given that your A/C has 1700 hours on it -- was there ever a snubber diode installed across the "S" terminal and ground on the Starter Relay? Without one, the voltage spike will destroy contacts over time...

There are a couple of options for starters, all subject to religious arguments :) -- see:

https://skytec.aero/product/lycoming-aircraft-starters/
https://bandc.com/product/lycoming-starter-homebuilt-2/
 
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Sounds like the electrical path from the battery to the starter or the return path back to the battery is compromised and not allowing sufficient current to flow to the starter. Need to start some testing with a multimeter to identify the component with the issue. Have you put a battery tester on the battery to see how it deals with high current loads? Once you start the plane, the battery is doing very little and can trick you into thinking it is performing well when it is really unhealthy. A carbon pile tester is only $15 at HF.
 
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Check for high resistance in the master contactor. You can do this easily by using a jumper cable to bypass the master, or by moving one of the cable connections on the master to the other side, thus bypassing.
Of course, this testing is best done with everything electrical turned off...
And, remember the proper protocol of disconnecting the battery negative while messing around changing positive side connections...
 
Similar issue

I had a similar issue around 80 hours on a replacement starter. It got progressively worse over 4-5 flights until only half a blade of turn on a WW prop. Seemed like a bad battery, volts went to zero when starting. New battery, same thing. Measured plenty of amps when starting, something shorted somewhere. Turns out is was the starter. The starter ohmed out fine when not cranking. I connected a jumper cable from my car directly to the starter, to eliminate all aircraft wiring, battery, and relays. Same thing.

Turns out the starter would short to ground when the drive gear extended and engaged the ring gear. Replaced the starter, no issues the 130 hours since.
 
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