Ford 8N Starter motor not working-High pitched wine, engine won't turn over.

[tmac196]

As noted in the title. The problem began 5 days ago with an occasional high pitched whine prior to the Starter properly engaging the flywheel and cranking the engine to life. Over the past few days this has become increasingly more frequent and now is present almost 100% of the time. I attempted late last night to get a video of the problem, but it was so dark all you can hear is the audio. I suspect it will be enough for those of you who have worked on starters before.

Here is the link:

The starter motor turns vigorously when the starter switch is depressed, but the Drive assembly (AKA the Bendix unit-as I have seen it referred to-) does not seem to be engaging.

Any ideas on where the problem might be? I did not have time last night to remove the starter assembly, but will do so tonight. Any ideas/suggestions about getting the starter assembly out easily will also be appreciated. I am aware about the two bolts connecting it to the flywheel housing, but the nuances of getting it all out in one swoop are what I am looking for.

tmac

 

[Soundguy]

the drive gear sets at the end of the starter shaft. when the starter spins up the drive suck in and engages the back of the ring gear.

if the shaft is dirty, rusty or greasy/oily, it won't suck in..

pull the starter carefully, don't let it come apart. clean the shaft and drive with brake cleaner.. then lube the shaft and drive with some spray silicone dry lube. no grease or oils.

post back

 

[eddie48]

I have to start by saying that I have never had an 8n starter out. However, there are 2 basic designs for the bendix on a starter. The first is a bendix that is physically thrown out by a separate solenoid attached to the starter motor. If this one has that, is the solenoid working? In the second case the bendix is on a helix and is thrown out by the inertia of the bendix and the sudden rotation of the starter shaft. In that case the usual problem is that there is glop on the helix which causes the bendix to stick. In both cases, it is important that you check the drive gear on the starter and the ring gear on the flywheel to be sure that both are intact.

 

[eddie48]

Just saw Soundguy's answer. I agree.

 

[metalsmith]

Yep not much to go wrong with a starter, either the bendix solenoid has failed, bendix is stuck and not engaging or of the worst, teeth missing on starter and or flywheel ring.
That whine is from a free spinning starter motor.

 

[tmac196]

"Is the solenoid working?"...Well, it does turn the starter motor on.

Would this same solenoid also be the one which engages the bendix/drive gear or is this only intertial driven in these tractors?

the drive gear sets at the end of the starter shaft. when the starter spins up the drive suck in and engages the back of the ring gear.

if the shaft is dirty, rusty or greasy/oily, it won't suck in..

pull the starter carefully, don't let it come apart. clean the shaft and drive with brake cleaner.. then lube the shaft and drive with some spray silicone dry lube. no grease or oils.

post back

 

[tmac196]

the drive gear sets at the end of the starter shaft. when the starter spins up the drive suck in and engages the back of the ring gear.

if the shaft is dirty, rusty or greasy/oily, it won't suck in..

pull the starter carefully, don't let it come apart. clean the shaft and drive with brake cleaner.. then lube the shaft and drive with some spray silicone dry lube. no grease or oils.

post back

I was able to successfully remove the starter. Had to remove the oil filter canister in the process, but it came out. I have not had time to clean it or to test it, but here are some pictures of the starter, the drive gear assembly and the ring gear. Do there appear to be any problems?

 

[chvfrk98]

Funny... My buddy and I just pulled his last week for a no-start issue... Would have been nice to know the thing could come apart! Either way the starter was fairly worn as the brushes were about to fall out. Bought a new starter and a new wiring harness was $18 so it's getting one of those too. All this after he finally put a new carb and a pertronix kit on it. We'll see.... May need a new battery after this.

 

[Soundguy]

well.. it's partially engages right now. if not hitting hte good teeth.. then it's sticking. depressing the washer on the spring at the end lets you drift out a pin and slide the drive gear off.

PS.. for those that are not familiar, this ford uses a start relay. not a flip out eloenoid... I saw it asked... this should clear it up.

 

[MikesTractor]

When you look at the ring gear through the starter hole, you a are looking at the unused side of the ring gear. The starter actually engages from the back side. To check for wear, you can carefully feel the back of the teeth(watch for steel shards and sharp edges) or just use a mirror and light. Rotate the engine with a screwdriver or small pry bar to see the whole gear. Use a piece of chalk to mark the flywheel so you know when you've gone all the way around.

Mike

 

[Soundguy]

yep.. back in post 2 it was stated it engages the back of the ring gear.

 

[MikesTractor]

Yeah.....guess I should have paid a little more attention. Sorry about that.

Mike

 

[tmac196]

Problem solved. Stopped at the local dealer today who showed me that the drive gear was worn and wouldn't be able to engage the ring gear properly when the starter motor spooled up. There are small cleats (for lack of a better word) between the part of the drive gear containing the spring and the portion which rotates and slides centrifugally which were worn down and not allowing enough torque to be applied to spin the drive gear up and to mesh with the back of the ring gear.

I purchased a new drive gear and reinstalled the starter, oil filter canister and all of the wires and was able to successfully start the tractor several times.

A great big "thank you" to all of you TBNers whose advice and expertise helps me keep the old girl running and makes a better tractor mechanic out of me each time a new problem arises.

tmac

 

[Soundguy]

it wasn't letting it suck in all the way. that pic you posted shows it only partially engaged.

it lasted a good long time though. testiment to it's maker!