# Yardworks blower gearbox problems...



## Blackstar (Dec 27, 2010)

Hey Guys... haven't posted in a while but have been doing a lot of reading and searching. I have an older Yardworks blower bought here in Nova Scotia from Canadian Tire back in Oct of 2001. It's a 10.5 HP with a 30 in cut. This thing has run great for years but I am now having several things happening all at once.

Last storm we had about 2 weeks ago I was running into a 3 foot drift of light powdery snow when the augers stopped spinning. I figured it was the auger gearbox again so I put it away in the shed and finished by shovel. 

Tried to start it again a week later and I think I cooked the 110V starter. Must have had some water in my gas and froze in the line. Now I'm just getting a rattling noise from the starter. Read up and watched video on this so I have an idea how to check and repair (I hope).

Winter before last I had trouble starting and it ran like crap all winter but it did run. Should have tried to remedy this but just never had the time. The motor runs but hunts, revving up and down except under a good load and she levels out. After dark one evening I noticed the muffler was glowing red. This is why I thought the muffler might be blocked. Anyway, Got it started this weekend after I pulled the muffler off and checked for blockage. I confirmed the worm gear in the auger gearbox was shot AGAIN... This is the third one I've gone through in about 5-6 years. Last year I replaced both sides of the gearbox casing, new bushing at end of shaft and new worm gear. Also installed 2 new shear pins and packed the gearbox with Moly based high pressure and low temp synthetic grease. This grease is still like the day I put it in.

Does anybody have any idea why I'm going through worm gears instead of shear pins? Suggestions on carb? Ran some Seafoam through the tank and carb and it made no diff... I'm thinking the starter has a bad gear or ring gear is bad. .. 

Please Help...

Glenn


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## ToroGuy (Jan 12, 2014)

Carb probably needes to be cleaned out and/or rebuilt. As for the gearbox do your augers spin freely on the shaft? If the dont they may be seized, resulting in the shear pins being useless.


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## Blackstar (Dec 27, 2010)

These are some pics I posted last year when I ingested a piece of firewood in my neighbour's driveway. The pic of the worm gear then is identical to the one I just removed yesterday. I hope these pics will expand to full size.


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## Blackstar (Dec 27, 2010)

ToroGuy said:


> Carb probably needes to be cleaned out and/or rebuilt. As for the gearbox do your augers spin freely on the shaft? If the dont they may be seized, resulting in the shear pins being useless.


Augers spin very freely. Last time apart I sanded down the shaft and applied a light coat of grease. I agree with the carb suggestion.

Thanks

Glenn


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## Shryp (Jan 1, 2011)

Are you rough on your equipment? MTD is known to break easy, but you still shouldn't be going through that many gear boxes. Are your shear bolts too tight? If you tighten them too much they will clamp the augers to the shaft and won't break like they should.


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## Mr Fixit (Nov 19, 2013)

Nova Scotia gets a serious amount of snow, especially in recent years. Do you ever blow a shear pin? If you don't maybe try a lighter shear pin for a test. I'm running my second snowblower with no gear box failures running over 42 years. I've blown one shear pin in that time. Christmas lights extension. My shear pins are not undersized for sure you'd think.


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## Colored Eggs (Dec 7, 2012)

For the muffler glowing read I would adjust the carb and make sure its well clean. The worst case you need to have your exhaust valve checked. Could be its not closing all the way and allowing combustion to hit the exhaust.


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## Kiss4aFrog (Nov 3, 2013)

_*I ingested a piece of firewood in my neighbour's driveway.

*_Well that explains the last time and there isn't any way around that, it happens. It going again begs the question did you hit something again, maybe just a big chunk of ice ??

Sounds like you are due for a carburetor rebuild. Sometimes you can get away with a mild tear down and spraying some cleaner at the passages but if not, overhaul with a good soak.

The starter might just be the drive gear or spring on the end of the starter motors shaft lost a tooth, too much play or broke. Need to take the starter motor off and inspect it before playing "what could it be". Why make twenty guesses at it before you've done anything to diagnose it. Pretty much anything to fix the problem will require it coming off so why not do it first and then ask about it ??


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## ToroGuy (Jan 12, 2014)

If the augers spin freely then the shear pins must be too tight or too strong. They should be snapping on you well before that gearbox blows.


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## Kiss4aFrog (Nov 3, 2013)

+1 , What he said.


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## BeerGhost (Dec 17, 2013)

*gear worn*

Wow that gear is really worn down in 2 years service. Whatever you used for lube didn't work .I would look into a different lube for that gearbox.

the worm gear rode over the gear teeth exploding the gearbox.

drill and tap the new gearbox for a grease fitting and fill it up every year.


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## Kiss4aFrog (Nov 3, 2013)

I don't think packing it full is a good idea. They aren't designed to be packed full. His gearbox had enough grease to operate properly as is. It wasn't a lack of lube that damaged it or any way some additional grease would have saved it.


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## Colored Eggs (Dec 7, 2012)

I have a question When you rebuilt the gearbox what type of grease did you use.


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## BeerGhost (Dec 17, 2013)

> Last year I replaced both sides of the gearbox casing, new bushing at end of shaft and new worm gear. Also installed 2 new shear pins and packed the gearbox with Moly based high pressure and low temp synthetic grease.


 
Maby try a lithium based grease this time


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## ToroGuy (Jan 12, 2014)

I understand a lack of lube can do that to a brass gear but can a "wrong" lube actually do that in 2 years time?


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## Shryp (Jan 1, 2011)

Was the grease you used designed for cold temperatures, or does it get hard as a rock and just cake around the gears?


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## Kiss4aFrog (Nov 3, 2013)

When in doubt you can always use a "00" grease. It's just barely grease and almost a liquid. It's used in a lot of riding lawn tractor geared transmissions and can handle the below zero stuff as well as the summer heat and it's a quality high pressure lubricant.
Available at Oreilly auto parts from Prime Line PN 7-06612 $10.50 for 32oz
That's just one brand and it's available from Valvoline and others and other suppliers.


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## Blackstar (Dec 27, 2010)

Shryp said:


> Are you rough on your equipment? MTD is known to break easy, but you still shouldn't be going through that many gear boxes. Are your shear bolts too tight? If you tighten them too much they will clamp the augers to the shaft and won't break like they should.


Not overly rough on my blower. Usually use 1st speed in heavy or deep snow with full or near full throttle. First time I broke the worm gear I wedged the edge of my shed ramp into the auger, second time it was a piece of firewood in a neighbours driveway. This time it was 3 feet of powdery light snow?? 

Shear bolts are loose. I can spin them with my fingers. One was slightly bent to an "S" shape this time. Just spoke to a local dealer here yesterday and he told me my shear bolts should be 1.5 inches long for the shear sections to match up to the shaft properly. Haven't had chance to check this yet but will today.

Thanks for your input.

Glenn


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## Blackstar (Dec 27, 2010)

Mr Fixit said:


> Nova Scotia gets a serious amount of snow, especially in recent years. Do you ever blow a shear pin? If you don't maybe try a lighter shear pin for a test. I'm running my second snowblower with no gear box failures running over 42 years. I've blown one shear pin in that time. Christmas lights extension. My shear pins are not undersized for sure you'd think.


I just asked the guy at the dealership yesterday if there were lighter weight shear pins and he told me he had never seen any?? I was thinking the same as you, make the pin easier to break. In all the years (13) running this one I've only taken out 1 shear pin but I bent a few. 

Thanks

Glenn


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## Blackstar (Dec 27, 2010)

Colored Eggs said:


> For the muffler glowing read I would adjust the carb and make sure its well clean. The worst case you need to have your exhaust valve checked. Could be its not closing all the way and allowing combustion to hit the exhaust.


That could be something... a stuck valve. It actually backfires out the muffler every now and then. That sounds like a summer/off-season job for me though. I'd have to remove the head. I was going to pull the carb after the season also. 

I've been looking over the various carbs in a PDF file I DLed on identifying Tecumseh carbs. Still not sure which one I have. Some have very little adjustments.

Thanks 

Glenn


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## Blackstar (Dec 27, 2010)

Kiss4aFrog said:


> _*I ingested a piece of firewood in my neighbour's driveway.
> 
> *_Well that explains the last time and there isn't any way around that, it happens. It going again begs the question did you hit something again, maybe just a big chunk of ice ??
> 
> ...


 Good sound advice. I am in a bind at the moment and was looking for a couple quick pointers. I realize I have to pull the starter and the carb but was hoping to keep it running til spring. Big storm coming my way Thursday. 

Starter and carb issues are delayed until off season but the gearbox thing has me baffled. The dealer says he has never heard of it happening this often before.

Thanks 

Glenn


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## ToroGuy (Jan 12, 2014)

Kiss4aFrog said:


> When in doubt you can always use a "00" grease. It's just barely grease and almost a liquid. It's used in a lot of riding lawn tractor geared transmissions and can handle the below zero stuff as well as the summer heat and it's a quality high pressure lubricant.
> Available at Oreilly auto parts from Prime Line PN 7-06612 $10.50 for 32oz
> That's just one brand and it's available from Valvoline and others and other suppliers.


This is the grease that I used after replacing my worm gear as well. Seems to flow well in the extreme cold. I believe it is the same as the Super Lube 00 grease?


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## Blackstar (Dec 27, 2010)

ToroGuy said:


> If the augers spin freely then the shear pins must be too tight or too strong. They should be snapping on you well before that gearbox blows.


Agreed. Another suggestion was weaker shear bolts but dealer doesn't have such an animal. I'm going to call around a bit more.

Thanks

Glenn


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## Blackstar (Dec 27, 2010)

BeerGhost said:


> Wow that gear is really worn down in 2 years service. Whatever you used for lube didn't work .I would look into a different lube for that gearbox.
> 
> the worm gear rode over the gear teeth exploding the gearbox.
> 
> drill and tap the new gearbox for a grease fitting and fill it up every year.


This was a very good high pressure grease used in the differential in my V-Star motorcycle. It was still very pliable after 2 winters. I don't think it was a lubrication problem. Like someone else mentioned... there may have been a chunk of ice in the snow that I ingested. But the shear pins should have protected the gearbox.

Thanks 

Glenn


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## Blackstar (Dec 27, 2010)

Colored Eggs said:


> I have a question When you rebuilt the gearbox what type of grease did you use.


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## Blackstar (Dec 27, 2010)

ToroGuy said:


> I understand a lack of lube can do that to a brass gear but can a "wrong" lube actually do that in 2 years time?


I can't see it. You can see in that older pic that the worm gear is worn in one spot only. The augers stopped suddenly and the impellor shaft kept spinning. Destroyed the worm gear ion one section. The gear this time around is worn in one section only. Same as 2 yrs ago. 

I'm starting to see now that it must be the shear pins aren't doing their job. I will take a pic later and post them to show the damage to one. Just bent a little. I will also slide the good on back on the shaft and see if the milled sections line up with the width of the shaft. 

Thanks 

Glenn


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## Blackstar (Dec 27, 2010)

Shryp said:


> Was the grease you used designed for cold temperatures, or does it get hard as a rock and just cake around the gears?


Good for extreme low temps. When I took it apart it was -12C outside and inside my shed and the grease had the texture of smooth cream. Very good shape for the cold. 

Glenn


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## Blackstar (Dec 27, 2010)

Kiss4aFrog said:


> When in doubt you can always use a "00" grease. It's just barely grease and almost a liquid. It's used in a lot of riding lawn tractor geared transmissions and can handle the below zero stuff as well as the summer heat and it's a quality high pressure lubricant.
> Available at Oreilly auto parts from Prime Line PN 7-06612 $10.50 for 32oz
> That's just one brand and it's available from Valvoline and others and other suppliers.


Never saw this product before. I'll check around for availability. Could this be too light for this application? 

Glenn


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## Blackstar (Dec 27, 2010)

Had some spare time today and pulled the carb off the blower and removed the jets for a cleaning. Main jet wasn't too bad. The one in the side, behind the little rubber cap was a bit dirty. Sprayed everything inside and out with carb cleaner and blew out with compressed air. 

Pulled the starter off (quit working while trying to start last time). Grinding noises. Starter gear has most of the teeth broken off. Flywheel is in great shape. Starter spins and solenoid kicks out smoothly. Just need a gear and a tool to remove that darn clip. 

I'll get a couple pics of the starter gear tomorrow. Still need to get the worm gear for the auger . Everything else in the gear box is good and looks like I have the correct shear bolts. 

Got the info needed for these jobs on this site and in the videos from the sticky section. Great forum here guys.


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## Shryp (Jan 1, 2011)

In one of the donyboy videos he stated he used pliers for years until he got the special tools. He says the tools make it easier, but if you are only doing it once you might just fight it for a little longer.


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## Toro-8-2-4 (Dec 28, 2013)

Lots of good comments here!
It looks from your pictures that some of the brass worm gear teeth are shaved down.

When you rebuild the gear box make sure there is not too much play in the bronze bearings. If you get too much or too little engagement between the worm and worm gear it will cause rapid wear. The brass worm gears always goes first as it is so much softer. Too much play or run out in either shaft may cause this.

You may want to try using a different grease. There have been several posts about this and you may want to take a look at them. Consider a 00 weight grease or a Mobil 1 grease they both will stay soft at low temperatures. Some people use a 80w-90 gear oil. The only problem is that the seals on your case may not hold it and it will leak out. 

Good Luck.


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## Blackstar (Dec 27, 2010)

I'm thinking of trying a different grease. The 00 sounds like a good one. When I replaced the worm gear last time I also changed the gearbox, both sides. It was cracked but also worn oval shape where the shafts run through it. All clearances checked out ok. 

The only thing I could see that was out of place was the washers on the auger shaft. I had forgotten to put a washer on either side of the worm gear inside the casing. Found them on the outside of the case this time around. My mistake and this could have allowed enough sideways movement of the worm gear, coupled with the 3 foot snowdrift with some possible ice hidden amongst the snow to shear off enough teeth to destroy another gear. 

I'll be a little more diligent this time around. 


So, what about the starter gear? Any ideas for a reasonably priced replacement? Never priced this item before.

Thanks for all comments...

Glenn


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## Toro-8-2-4 (Dec 28, 2013)

You need to get a P/N for your starter and go from there. If you go to a site like jacks small engine you may find a complete parts list and exploded drawings for your Yardworks machine.

The 00 grease is readily available on line in the Stens or Oregon brand. I have not found the Prime Line on the Web or in any store near me in MA. It is not available from O'Rielly's on line. If you have an O'Rielly autoparts store near by give them a try as they do have it for a very good price.

I know you said your shear pins are not too tight and the augers are free to rotate. Since you never broke a pin, it may be a design flaw. Make sure the groove in the pins are where the shaft and auger meet. You can also file or Dremel tool a deeper notch in them to make them even weaker. I assume they are 5/16 diameter bolts. 

It is interesting the gear casing has only 5 bolts and you have a 10hp machine with a 30" width. My 8hp 24"Toro has 8 bolts holding the two halves together. Adding a few more bolts may stiffen it up and distribute the load more evenly so it may not stress the case as much under extreme loads. I am just thinking out loud on this one. It may not matter but it is worth some thought.

Good Luck


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## Blackstar (Dec 27, 2010)

Some good ideas there Toro-8-2-4. I'm in Nova Scotia so I have a different line of auto or Hardware stores to search. I was thinking the same thing about weakening the shear bolts a little more. 
Not sure exactly of the thickness of the bolts but they are 1.5 inches long and the clots line up with the edges of the shaft.

I was talking to my brother today and he said that he saw one that his friend had. The ends of the auger inlet housing, the main body part, was kind of loose... had some give to them. If the guy forced the blower to turn, working it back and fourth in a deep drift for example, it would cause enough play in the auger shaft that he could tear up the worm gear. 

Something else to think about...


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## Toro-8-2-4 (Dec 28, 2013)

I was talking to my brother today and he said that he saw one that his friend had. The ends of the auger inlet housing said:


> Sounds like worn bronze bearings causing too much play in the worm gear shaft.


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## Blackstar (Dec 27, 2010)

Toro-8-2-4 said:


> Sounds like worn bronze bearings causing too much play in the worm gear shaft.


Yes, in that particular one. But I think Mine are within tolerance.


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