Starter engagement (not)

Hoping someone has some insight into an issue I've been fighting for a couple of months. The starter bendix on my ancient Snorklelift tb50 lift jammed and ate the ring gear. I had the starter rebuilt and found what appears to be a perfect match flywheel (ring gear looked pristine to me) and installed them. Seemed great at first but then the grinding started and now I'm back to the starter just spinning when I try to start it. I bought a Brand New ring gear but I'm hesitant to swap it because it looks to my naive eye only marginally better that what's on there...or I should say what's on there doesn't seem all that bad to me. There just doesn't seem to be enough mesh between the gears. Is this a 'normal' amount of mesh or ?

The little gear looks too small.
What engine does this have exactly?

I’m questioning whether you have the correct drive gear.

It's a wisconsin vh4d. "Supposed" to take a mbg4141 starter which is, in theory, what I have. I've seen a bunch of bendix drives since I started this ordeal and they all look exactly alike. Even the original one that got eaten is, aside from the tips being rounded over, the same as what's on there. I'd love to find a larger diameter drive gear, but afaik there is no such thing. I'm ready to try the crazy stuff - like welding a bead on the 10 teeth and shaping them smooth with a grinder. 1/8th inch should do it.

Before you weld, I'd try moving the starter closer to the flywheel. Open up the mounting holes a bit?
Are you sure the original starter was actually original? From quick searching there is a 9 or 10 tooth gear, 36mm or 39mm. You have the bigger one it seems?

Is that picture with the bendix kicked out and touching the flywheel, or pulled back? Just wanting to make sure since the angle of the picture and the taper of the teeth on the starter could be deceiving.

If that is all the contact it makes, that would be concerning and something is definitely wrong. Any chance you have an old school motor/starter rebuild shop in the region (if any survived 2020 that is)? Hell, even small engine shops might have some info since they ran those VH4Ds in chippers, pumps and everything else you can imagine.

skata said:

Before you weld, I'd try moving the starter closer to the flywheel. Open up the mounting holes a bit?
Are you sure the original starter was actually original? From quick searching there is a 9 or 10 tooth gear, 36mm or 39mm. You have the bigger one it seems?

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Yup, 10 tooth, CCW.

skata that's super interesting about the 36 vs 39mm. I've not tripped over that. Can you point me to a reference? I don't have a micrometer big enough to measure it, but measuring with an inexact tape measure says the one that came on it to me is less than 1.5" so I'm guessing it's smaller than 39mm...I'd love to find a replacement 39mm bendix. Yeah, opening the mounting holes is definitely on the list...and possibly less fragile than welding on this mystery metal, but I also will have to grind out the front of the "ring"...there's about a 3 inch hole the starter fits into and there's a matching raised ring that exactly fits that hole. grinding the front half of that ring away is doable. Last night I bought Yet Another starter so I'll have a spare when I destroy this one trying my hacks. . I've repaired the original, and bought (and returned) 3 others for various reasons...mostly my own stupidity since they didn't "just work" with the original flattened ring gear or they self-destructed upon first use (bendix gear ripped out of it's pressed in mounting). I'm afraid the new starter + new ring gear will work just enough to wear down and eventually leave me stranded in the air...again.

MarshallPowerGen said:

Is that picture with the bendix kicked out and touching the flywheel, or pulled back? Just wanting to make sure since the angle of the picture and the taper of the teeth on the starter could be deceiving.

If that is all the contact it makes, that would be concerning and something is definitely wrong. Any chance you have an old school motor/starter rebuild shop in the region (if any survived 2020 that is)? Hell, even small engine shops might have some info since they ran those VH4Ds in chippers, pumps and everything else you can imagine.

Click to expand...

Yeah MarshallPowerGen that's a picture of it kicked out and since it isn't meshed it can't get inertia to spin back. There's still a couple of old school shops within 90 miles and it's been repaired by both (!). I did a lot of flailing before I finally pulled the flywheel out and realized how damaged it was. One of the shops has been great but this is apparently beyond them. I sent them this picture yesterday and he just agreed that the gear needs to be bigger. I'd love to find that 39mm bendix! I'm really just guessing but I found specs for a similar mbg4141 on an ad on amazon and it says the diameter is 36.8mm...39mm vs 36.8 is still almost 1/10th of an inch...granted I have to divide that in half but still, every little bit helps

Optimist said:

Hoping someone has some insight into an issue I've been fighting for a couple of months. The starter bendix on my ancient Snorklelift tb50 lift jammed and ate the ring gear. I had the starter rebuilt and found what appears to be a perfect match flywheel (ring gear looked pristine to me) and installed them. Seemed great at first but then the grinding started and now I'm back to the starter just spinning when I try to start it. I bought a Brand New ring gear but I'm hesitant to swap it because it looks to my naive eye only marginally better that what's on there...or I should say what's on there doesn't seem all that bad to me. There just doesn't seem to be enough mesh between the gears. Is this a 'normal' amount of mesh or ?
View attachment 222810

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I'm no expert on Wisconsins but there's a Facebook group called Wisconsin air cooled engines. The logo is a clock with a draft horse. Join it and ask there. Some of those guys are very experienced and may be able to tell you exactly what to do to remedy your issue. That bendix looks way too small to me. Good luck!

tractormech said:

I'm no expert on Wisconsins but there's a Facebook group called Wisconsin air cooled engines. The logo is a clock with a draft horse. Join it and ask there. Some of those guys are very experienced and may be able to tell you exactly what to do to remedy your issue. That bendix looks way too small to me. Good luck!

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Awesome idea!

Optimist said:

Yeah MarshallPowerGen that's a picture of it kicked out and since it isn't meshed it can't get inertia to spin back. There's still a couple of old school shops within 90 miles and it's been repaired by both (!). I did a lot of flailing before I finally pulled the flywheel out and realized how damaged it was. One of the shops has been great but this is apparently beyond them. I sent them this picture yesterday and he just agreed that the gear needs to be bigger. I'd love to find that 39mm bendix! I'm really just guessing but I found specs for a similar mbg4141 on an ad on amazon and it says the diameter is 36.8mm...39mm vs 36.8 is still almost 1/10th of an inch...granted I have to divide that in half but still, every little bit helps

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From the quick searching I did, the 10 tooths are usually 39.xxxmm

So the facebook suggestion was a really good one. One of the suggestions I got there was that the shroud that the starter mounts to fatigues and the starter droops, so you have to fashion a bracket to keep it square. I don't think that's my problem, though it is a good suggestion. No amount of prying got the starter near where it needs to be. But, while trying that, I stepped back and looked at the big picture and I now think my shroud has shifted...maybe it happened when the starter ate the ring gear, or maybe that just loosened it and the smacking of the two has made it progressively worse, but from the outside the shroud is definitely farther from the flywheel at the starter, than it is on the opposite side. Like 1/2" on one side and 1/8" on the other. I should have noticed this earlier. Now I have to pull the flywheel again and see what kind of adjustments are possible.

Hi optimist,
Yes you have to get the Bendix deep into the gear but it sounds like your onto something with the shroud moved.
One thing you said which is a concern is you needed the inertia to get the Bendix to return to the retracted position.
This is never the case so the Bendix is ether not moving on the lead screw freely or a very fine light spring has broken or missing which keeps the Bendix from engaging the ring gear when the motor is running.
I can explain further if needed but inertia is not used to disengage the Bendix.
You can weld the Bendix as a last resort but the heat travels down into the one way clutch and melts all the grease out which can not be put back in easily.
Cheers

At whatever point and whatever you assemble to try again, Paint the teeth of the Bendix with black spray paint.
Connect and spin a few revolutions. Remove the starter and observe the wear pattern in the paint.
You can then immediately determine the meshing pattern, full length-short or shallow-deep.

So...I had to put the battery on the charger so haven't had the chance to start it yet, but the shroud was definitely a core problem. 4 bolts mount the shroud to the block positioned around the crank...3 in my case since one was missing...and the 3 holes that did have bolts were beyond egg-shaped...at least 1/4" out of position closest to the starter. after re-positioning and bolting it back up there's tons of mesh. wish me luck...now I need to build a bracket for the starter to reduce future misadventures.

Optimist said:

So...I had to put the battery on the charger so haven't had the chance to start it yet, but the shroud was definitely a core problem. 4 bolts mount the shroud to the block positioned around the crank...3 in my case since one was missing...and the 3 holes that did have bolts were beyond egg-shaped...at least 1/4" out of position closest to the starter. after re-positioning and bolting it back up there's tons of mesh. wish me luck...now I need to build a bracket for the starter to reduce future misadventures.

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Sounds like you found it. Very good.

I did! Thanks. Still a little anxious when I hit the starter but so far it starts right up like the old days with no nasty clatter. Knock on wood. Still shake my head about it...if I hadn't been on the way to pulling the "new" flywheel to put on my old flywheel with new ring gear because I couldn't think of anything else to try, I wouldn't have pulled off the flywheel screen which is how I noticed the offset of the flywheel in the opening. I would never have thought that the shroud was out of place without that.