Sky-tec failure

[Andy]

Another VAF thread with a link to a rebuilder and parts supplier:

https://vansairforce.net/threads/sky...ebuild.208442/

[Andy]

They were working on a change for the solenoid on the starter for an issue that sounded like this and may now have a field kit.

It took a while but I found the service letter - https://skytec.aero/wp-content/uploa...1-Rev.-New.pdf.

As I have researched this starter I have come to the conclusion that many of the internal components are from Bosch automotive starters. If that's true then almost everything could be field replaced, except perhaps the housing and the drive pinion, even if Hartzell won't overhaul them.

There seem to be Chinese clones of the solenoids, brushes, and complete brush assemblies. They may be ok but I think I'd prefer genuine Bosch parts if they can be found.

[Bill Tew]

Andy - Thanks for the information. At the moment my starter is working fine. From some discussions on the web, the starter solenoid is often the problem with intermittent issues. Replacing it is simple and in expensive. Replacing mine today and time will tell if that fixes the problem. If not, the starter itself would be the next.

[Bill Tew]

I replaced my starter solenoid - was easy without having to remove the starter. Since the problem was intermittent - time will tell if that fixes the problem.

It appears that any of the 12V automotive starter solenoids with the right fitting to engage the starter gear yoke will work. Available from number of sources for less than $30. Ford starter solenoids for Lincoln and Crown Victoria have the right fitting - photo below.

To connect the new solenoid to the actuator fork, pull the starter gear froward to engage the ring gear and hold in place with slight tension on the prop. This pulls the fork back and gives enough clearance to hook up the solenoid.

Bill


IMG_1961.jpg

[Andy]

Thanks for the report.

Did you find any contamination between the solenoid piston and the main housing that could have jammed the solenoid?

Does the removed solenoid pull in positively with 12 V applied to the small terminal and ground on the solenoid body?

I purchased a spare solenoid but I have not yet decided whether to fit it at condition inspection or just keep it as a spare.

I emailed Hartzell support and asked what failure condition had prompted the service letter but they didn't bother to reply.

The problem I have is that, at first cold start attempt, sometimes the starter buzzes but makes no sign of turning the prop. This happens even if the prop was positioned at TDC where there is almost no resistance to rotation. Second attempt always turns the engine.

[Bill Tew]

My starter problem was infrequent but often enough to keep me close to my home field. No prop movement could occur on first start out of heated hangar or at some distant location. When it did occur, could hand prop and get home after which everything works for a while. It truly random.

The suspect solenoid was woking when I removed it - no corrosion or other obvious defect. Had 6 starts on the new one with no issues. Time will tell if replacing the solenoid solves my problem.

[Bill Tew]

My starter problem was infrequent but often enough to keep me close to my home field. No prop movement could occur on first start out of heated hangar or at some distant location. When it did occur, could hand prop and get home after which everything works for a while. It truly random.

The suspect solenoid was woking when I removed it - no corrosion or other obvious defect. Had 6 starts on the new one with no issues. Time will tell if replacing the solenoid solves my problem.

Update on Sky-tec starter issues - Since replacing the solenoid on my EX-2 Sky-tec starter, I have had no failures to turn over in about 20 flights. Guardedly confident that the problem was a faulty solenoid.

[Rick Bosshardt]

Good news, Bill!

[Andy]

It took a while but I found the service letter - https://skytec.aero/wp-content/uploa...1-Rev.-New.pdf.

As I have researched this starter I have come to the conclusion that many of the internal components are from Bosch automotive starters. If that's true then almost everything could be field replaced, except perhaps the housing and the drive pinion, even if Hartzell won't overhaul them.

There seem to be Chinese clones of the solenoids, brushes, and complete brush assemblies. They may be ok but I think I'd prefer genuine Bosch parts if they can be found.

Hartzell has removed SL-201 from their web page and a representative says it was never officially released. Field repair is not approved and there is no repair kit.

If they fail outside warranty Hartzell's position is that they are scrap.

Good thing we don't need Hartzell approval for experimentals.