Posi-Drive Starter Drive

[Dean]

Anyone have experience with the late model, so-called Posi-Drive starter drives.

I have tried two (junk) Indian made aftermarket 6V, 8N starters within the last 22 months. Both came equipped with the late style Posi-Drive starter drive which I did not change because I (as yet) have no way to remove it.

The first starter motor failed in about 18 months due to dead spots on the commutator and eventually just about all dead spots (out of 90 day warranty). The second still works after about 6 weeks but the drive jams into the ring gear and does not release. Yes, it worked OK for about a month but it now jams no matter where I position the engine before starting.

I have never had this problem with the OEM, spring style starter drives.

Anyone have useful experiance?

Dean

 

[Jim L WA]

I have one on my 2N, and it has worked fine for around 3 years now, but it is on the O.E.M. rebuilt starter.

 

[Dean]

Interesting.

Thanks for the information.

Aside from the dead spot issue, I have discovered multiple other quality issues with both (actually 3, now that I recall) of the junk aftermarket starters that I have experience with.

Dean

 

[R Geiger]

I have two of them that I purchased from YT. they both are on OEM starters and both are working just fine 5 years on one and about 7 on the other.

 

[soaked]

Have you tried squeezing the drive in a vice like this?

The rest of the assembly comes apart.
I used a small jewellers screwdriver to get the clips off.

May find broken parts.

Part # 17 is a rubber bushing that allows squeezing, to get the last clip. I cut a short bit of pipe, and grinded a couple windows out, squeezed in my vice, till the clip would pry out.

The little spring loaded piston can be reset using a piece of 3/16 wide zip tie, wrapped in the slot.

Last pic showes the black zip tie, in the slot. Rotating a bit more, allows the tie to come out, leaving the piston reset.

Maybe someone else can figure a modification to improve performance.

Mine hit real soft with a 12 volt lawn mower battery, using jumper cables. Only able to turn the engine about half a revolution.

Mine also retracted when on a long screwdriver, turning on the wire wheel.
Got it spinning, then held verticle, and it retracted.

 

[Dean]

Interesting, and good information.

I will try the vice procedure to remove.

The quality of the aftermarket starters is so poor that I'm wondering if alignment problems, tolerances, etc., are causinig the drive to misalign with the ring gear and fail to disengage???

Dean

 

[soaked]

This domed shaped piston must jump the square edge of the gear on the right, to allow the part # 5 to spin back to reset. Seems the drive gear #1 has scratch marks showing the leading edge wear when starter moving ring gear. And, wear marks when ring gear is turning the starter drive when engine starts. Not sure on mis alignment-
Your ring gear has the tooth bevel facing the starter drive gear?

 

[Hobo,NC]

Nice work, I am gonna add Starter Drive for a key word if I need to search it for myself are others....

 

[Dean]

Yes, of course.

Tractor has only 1,100+ hours but there is a spot on the ring gear where teeth are worn.

I have learned by experiance that the aftermarket starters (at least one) with the new style Posi-drive starter drives will lock up even if I rotate the engine such that it is in a position where the ring gear teeth are undamaged. Yes, I have removed the starter, inspected the ring gear teeth, and reassembled things such that next start will engage undamaged ring gear teeth.

I have found that the junk aftermarket starters (every one that I have inspected) lack the steel ball that should be in the receptacle for which intended to keep the drive end bearing housing aligned with the field frame.

Though I have maintained such alignment upon assembly and tightened the starter attachment bolts accordingly, I wonder if starter torque and/or poor quality control of junk aftermarket starters might contribute to drive/ring gear interference resulting in drive/ring gear-hang up.

Trying to determine if my issue is drive or junk starter/drive related.

Thoughts?

Dean

 

[wore out]

"the junk aftermarket starters (every one that I have inspected) lack the steel ball that should be in the receptacle for which intended to keep the drive end bearing housing aligned with the field frame"

The indexing of the "drive end" and the starter's "belly" would have NO effect on the operation of the starter, as long as it is close enough to allow the though bolts to be inserted and snugged up all will be well.

On the other hand, indexing between the COMMUTATOR end that carries the brushes and the 'belly" IS important for the starter to operate at it's full power potential.

 

[JMOR]

(quoted from post at 00:45:51 11/08/20)
"the junk aftermarket starters (every one that I have inspected) lack the steel ball that should be in the receptacle for which intended to keep the drive end bearing housing aligned with the field frame"

The indexing of the "drive end" and the starter's "belly" would have NO effect on the operation of the starter, as long as it is close enough to allow the though bolts to be inserted and snugged up all will be well.

On the other hand, indexing between the COMMUTATOR end that carries the brushes and the 'belly" IS important for the starter to operate at it's full power potential.

ow! that is useful! :twisted:

 

[Dean]

Good advise.

Neither of my junk aftermarket starters have the indexing ball on the drive end.

I was careful to keep the indexing notch in position upon installation.

Dean

 

[Dean]

Yes. Ring gear is OEM, and tractor has just over 1,100 hours.

Dean

 

[Tim PloughNman Daley RIP]

Don't bet on it, hours that is. The Proofmeter hour meter doesn't register actual hours the engine runs, plus, many Proofmeters failed and were disconnected. If Proofmeter shows "1100" hours, don't believe it is an actual accurate showing of actual hours the tractor ran.


Tim Daley(MI)

 

[Dean]

Trust me, the hours are correct, and you would agree if you inspected and operated this one.

Dean