What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Starter Spins but does not engage

RV6_flyer

Well Known Member
Benefactor
I have an Intermittent problem that I have not seen before and do not understand.

I am using a Skytec Flyweight PM Starter. I have been using one for over 2,750 hours and 16-years. Did a swap with an overhauled unit about 200 hours ago.

Several times I have tried to start my engine (Lycoming O-320) and I could hear the starter spinning at high speed but it would not engaged with the starter ring gear so the prop did not turn. Cycling the starter switch and the master switch, every once in a while it would engage and the engine would start normally. Did it this morning on my cold start but had no problem on the next two hot starts.

I have three (3) spare starter solenoid from Skytec as I am familiar with the issues of the solenoid failing. What I do not understand is how the starter will spin and the gears not engage. I was under the impression that the design of the Skytec PM light weight starter was that the gear would engage and then the contact was made to spin the starter.

I will be taking my 82.5 year old mother on a cross country trip from Kalifornia to Pennsylvania next week. Yes she can get in and out of the airplane without help and has flow in it before. (Pittsburgh to DC and last Sunday from SoCAL [CCB] to the SF Bay Area [RHV] and loved it)

I listed my condo for sale on the 15 and 23.5 hours later it sold. I retired after 29.5 years of service at Boeing on 06 September 2013 and will be relocating to Southwestern Pennsylvania to be near / with my mother. We will be traveling by RV, airline, and car to places that she wants to see.

Desire to get this issue solved before heading east next week. Yes I am open to buying a new starter but would prefer to KNOW what is the problem with the one that I have as the design has served me well for over 16-years and 2,750 flying hours.
 
Had the problem years ago in the Archer II

Many years ago I had that problem when the pinion did not slide forward to engage the ring gear when power was applied to the starter. In that case following my mechanic's instruction I manually slid the pinion forward to engage the ring gear manually with a screwdriver then it started and threw the pinion back into the disengaged location. Later I read that you should not lubricate that open end of the started because this can cause contamination build up and make the gear slide from the starter disengaged position unreliable. There is a certain amount of force required to overcome the longitudinal inertia of the pinion and either weakened driving force or increased resistance could cause that intermittent failure.

Bob Axsom
 
Have you checked the Skytec troubleshooting guide yet Gary? Not sure if it covers that case, but sounds like you might have to give them a call. I haven't had that issue, and have thousands of hours on Skytecs between numerous airplanes.

I'd guess Bob's problem was the Bendix on the old boat-anchor starters. It was a sticky Bendix that lead me to my first Skytec!
 
Have you checked the Skytec troubleshooting guide yet Gary? Not sure if it covers that case, but sounds like you might have to give them a call. I haven't had that issue, and have thousands of hours on Skytecs between numerous airplanes.

I'd guess Bob's problem was the Bendix on the old boat-anchor starters. It was a sticky Bendix that lead me to my first Skytec!

Have checked the online troubleshooting guide as well as doing a Google Search. A phone call Monday morning is on my list of tasks for the day.

Yes it does sound like an old Bendix of the old boat anchor stater.

After a couple of thousand hours on Skytec starters, this is something that I do want to get to the bottom of.
 
Hi Gary

Had this problem with the Skytec on my RV7 it was the engage solenoid inside the starter, nothing but send it back to skytec to replace/rebuild:(
 
I will assume on this one but as Jerry said, the solenoid that engages.
The start has two parts, the main bigger portion that provides the power to turn the gear that is at the end of the shaft. And the other smaller portion which pushes the gear out and makes it engage the flywheel.
If you are hearing it just spin at a high rate then I would say its not engaging. Have you tried playing with the solenoid on the starter? 12v system? well you can put some power to the solenoid its self and see if it pushes the shaft out (should be able to hear it).
But then yet again.. This is just some automotive info. What do i know about airplanes. haha

Does ur starter look anything like a car starter?
How about this video... http://www.youtube.com/watch?v=9PWG6Il_ZJI
 
Last edited:
Have seen this symptom before. In this case the solenoid retainer screws had backed out of the solenoid, in fact one was missing. Larry
 
One reason why starter spins but does not engage

Sky-tec 149-12LS. See photo. Plastic teeth wear down. Starter spins but will not turn pinion/bendix
 

Attachments

  • 2F4CBAD3-38F0-4FC0-BF35-9CF0FDDA7033.jpg
    2F4CBAD3-38F0-4FC0-BF35-9CF0FDDA7033.jpg
    220.4 KB · Views: 401
Actual cause

I never followed up with what caused the actual problem back in 2013.

The starter solenoid on the firewall was bad. It was replaced 11-13-2013 and the problem has not returned in the last 600 hours.
 
I had a similar problem on a Sky-Tec 149-NL. Sometimes would engage, other times not. I disassembled and inspected the starter and drive, found the shaft the gear slides on had a clean break. I tried to order the part, but, Sky-Tec didn't supply replacement parts (this was in late 2016).
 
Back
Top