Dynatron starter won't turn over my 91

[cyclenut]

Starter was working fine, but all of a sudden wouldn't crank my 91 and got warm. I pulled it apart, and the brushes and stator look good. While I was putting it together again, I noticed that if the bolts were loose, it would allow magnets to pull the stator forward where the brushes would not be making full contact.. Could this be why it was so weak and got hot.. In that condition it would still crank my os 50 just fine. Any way once I got everything back together, I tried to spin the 91 again and it seems that tightening the two bolts did the trick.. Anybody else have any experience with getting a sick dynatron going? Btw this is a fairly new one that I picked up from amain in the spring. Tried using a 6s 5000 with it, but the switch burned up when the contact stuck. I put a new switch on and have been using it hooked up to the car for that first start of the 91 for the day, then an 18v drill battery after that first flight.

[rcflier1]

all I can say is I,ve been using mine for years with a 6cell/5000 for my 91 and never a switch issue. it is rated for 24 volts.you must have a few issues.maybe a bad winding, causing high current draw.

[ticedoff8]

Personally, I use an old Hobico 12v starter with a 3S 2200mAh LiPo.

That starts my YS 120SR-X and YS 60SR with no problems.
I used it on all of my YS 91SR-3DS (when I had 91SR motors)
I also used it on my OS 61, 70 & 91 (when I had OS)

When I need some extra kick, I will use a 4S 2200mAh LiPo.

I never saw the need to by the Dynatron - they were too expensive for me.

If the 91 is hydro-locked, then I could see why the motor might stall and get hot.
But, if it is running free and easy on the motor, then it shouldn't get hot.

But, I typically run the starter for 2 or 3 seconds before the motor catches.
I think the longest I've run the Hobico was 10 or 15 seconds - and then it gets a little warm.

[cyclenut]

Yeah, motor wasn't locked as I could turn the starter shaft by hand.. It is like the starter was really weak for some reason. I just ordered a 5s 3000 20c turnoff lipo to see if it does a better job than the car battery. It was getting annoying having to walk back out to the car to start the heli. Especially with a new tight clutch liner. Hopefully my tightening up the bolts in the starter, and picking up the 5s pack will make the difference. If not, I have the option of sending the starter in for repair, or can buy a whole new motor for less than half the cost of the starter when new.

[ticedoff8]

You didn't mention "... a new tight clutch liner" before

My guess is the clutch leafs are over extended and dragging on the liner.
If you spin the engine and you can feel the head trying to turn, they are extended too far

Pull out the motor and press the leafs back into position on the clutch.
Then, see if the dynatron starts spinning it like it used too.

[cyclenut]

after our discussion on the other thread, I have replaced the clutch shoe, so it is a brand new one. the issue I hit with the starter is that it didn't have enough power to turn the crank over even one time. it was just really weak. The clutch shoe spins freely in the clutch bell, but since I hit the starter issue, I haven't started the engine, so I'm not sure how grabby it will be once the motor is running 5-700 rpm, but that isn't what is causing the starter issue. I am hoping my dis-assembly/re-assembly combined with the 5s lipo showing up today will solve the cranking issue.

[cyclenut]

The 5s and the tighter bolts made all the difference. No issues starting up the 91 today and the new clutch shoe made a big difference in that at idle, the head was barely catching.. Like 1rpm or so