# Toro 521 Gear Issue



## WondrousBread (Nov 30, 2018)

Hello everyone, my name is Chris. We've recently come into possession of an early Toro 521. It belonged to my mum's uncle, who bought it new. He used it until he died, and then his brother (my grandfather) used it for years. My aunt used it until two years ago. They said that it seemed to have gearbox issues.

I performed some basic maintenance, and it is now running. The spark plug was loose (pulled it out with my fingers), and there is still a strange issue whereby pressing the primer button drips fuel from the mouth of the carb. There is no air filter, not sure if that is normal but I will be acquiring one and making it fit. Also will be acquiring an inline fuel filter. The engine idle is a bit rough, but I think its down to cleaning the carb and tuning it.

The reason I am posting is that I found a strange issue. The Toro does not drive forwards or back. It can be pushed forwards, but not backwards. It resists attempts to turn it, not sure if that is normal. I removed the drive belt, as the "clutch" handle does not seem to engage or disengage anything, and I didn't know if starting it would cause it to leap forward. Upon removing the bottom cover, I found a few things:

1. The friction wheel looks to be glazed over (expected, will order a new one provided I can rectify the other issues).

2. The spring that is supposed to hold the friction wheel assembly away from the spinning drive wheel is broken, so that explains my lack of clutch response. Will also need to be repaired or replaced.

3. This is the weird issue that has caused me to start this thread. There is a very large gear (the largest in the unit) connected to the axle. This gear seems to be contacting the pulley that the drive belt wraps around, just barely. The edge of the gear shows wear. I can take a picture later when I get a chance, as that might make it clear. None of the adjustments in the Toro (nor in the instruction manual) seem to be about moving this gear around. The strange part is that the gear seems to be perfectly installed, as it engages the other gear properly and everything else lines up. It is just this one pulley that seems to be in the "wrong place".

Searching has yielded no results, so I am just curious if anyone else has encountered a similar issue before, and how they fixed it. Thanks, Chris


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF Chris


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## tpenfield (Feb 24, 2015)

:welcome: Chris . . .


I had a similar observation on a 1980's vintage Toro 3521, which is the smaller engine version of the 521. (I also have a 1988 521which has been a great machine). If the drive belt is missing or loose, stretched, or over sized I noticed that the drive pulley will come in contact with the teeth on the gear and start to wear the teeth down. The drive pulley seems to be on a spring-loaded bracket that creates some tension on the drive belt. With the proper belt installed the pulley is pulled clear of the gear so there is not contact.


The situation may resolve itself once you have all the proper parts (belts/springs, etc) in place. I'd keep the lower cover off of the chassis until you have a chance to get it all working and make sure there is nothing rubbing up against a gear or pulley.


BTW - the 521 is a great candidate for the Predator 212cc engine upgrade. It turns that machine into a little monster.


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## Grunt (Nov 11, 2013)

WondrousBread said:


> strange issue whereby pressing the primer button drips fuel from the mouth of the carb. There is no air filter, not sure if that is normal
> 
> 1. The friction wheel looks to be glazed over (expected, will order a new one provided I can rectify the other issues).
> 
> ...


 
Hello and welcome to SBF Chris. 


Pushing the primer button WILL cause gas to drip from the carb, totally normal.


Snow blower motors do not have air filters because condensation would freeze them and block air flow, and there is really no dust to be ingested in the winter.


You can use brake cleaner or alcohol to clean the friction wheel and drive disk. Unless the rubber is worn or chewed up, no replacement necessary.


The gear may be hitting the pulley because the axle bushings are worn and allowing the gear to move forward. A picture of your problem would help a member make a more accurate solution. Could the broken spring be causing this??




Replace fricton wheel-




 


Carb rebuild-


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## WondrousBread (Nov 30, 2018)

*Found the problem*

Thank you everybody for the warm welcome 

Wow, I appreciate all the responses. tpenfield is absolutely correct, the pulley is only hitting the gear because there's no belt tension (and I was wondering why the drive belt was so tight). I'll be getting a replacement anyways as mine was deformed, and I'll probably replace the auger belt while I'm in there. Strange that the auger belt has it's own dedicated tensioner, but the for the drive belt the pulley doubles as the tensioner. 

Also, thank you Grunt for the rebuild video. Luckily these carbs are simple, I have been spoiled by EFI (my only "real" engine repair experience is with cars, otherwise it's been mostly maintenance) and I get lost when there are tons of screws and adjustments. 

I'm going to try fixing the spring by removing it, heating it, and twisting the edge over to make a new "hook" shape. If it doesn't work, all I've lost is a broken spring. 

I found there were a lot of engine options, but since we have relatively light duty on my driveway, I'm sure the existing one will be adequate. Also, since it's been in the family so long, it feels right to keep it original as long as possible. 

I took some pictures, but my flickr is acting up so I can't upload them as yet. I will try again later, that way if anyone else has a similar problem they can find my thread and see how to fix it. I'll also take some pictures once everything is fixed, maybe I'll even make a video 

Thanks again everyone


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## paulm12 (May 22, 2015)

I have noticed that with the drive mechanism spring released the gears can contact the pulley. Makes a noise when moving the machine around. see pics, machine is up on its housing, one is when I hold the parts together. Also see wear marks on pulley. This will be resolved with reattaching the spring. 
.


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## WondrousBread (Nov 30, 2018)

*Solved*

Hi everyone  

I sent a reply yesterday, but it hasn't appeared. Perhaps a mod disapproved it for some reason, I will re-read the forum rules accordingly. As stated before by tpenfield and paulm12, the drive wheel does contact the axle gear when the belt is off due to the tensioner spring.










Replacing the belt solved the issue (I bought a new one, as the old one was deformed).

I managed to fix the spring for the friction wheel return. Basically I just cleaned the spring with de-greaser, clamped it in a vise, heated the broken end with a propane torch, twisted it with vise-grips into the correct shape, and heated and stretched the end of the coil slightly to restore the correct length. A new one will be ordered, but for now I have a functional clutch. 

As a slight sidebar, the Toro 521 is an incredibly pleasant device to work on. I can see why there are so many snow blower enthusiasts out there, it's a blast. Everything is easy to reach and simple to service, but it's all compact and reliable. This may be the beginning of an addiction.

Now it just seems to be down to adjusting the controls & transmission as per the manual from Toro, lubricating everything, and rebuilding the carb based on the helpful video that Grunt provided. After that, it's on to rust repair 

Thanks all, I will provide some more pictures of the unit as I progress. 

P.S This really is one of the friendliest forums on the internet.


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## UNDERTAKER (Dec 30, 2013)

*ALOHA From The Paradise City. :smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027:*


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## WondrousBread (Nov 30, 2018)

Hi everyone, had to make a post in the New Members section before I could respond to this thread  Meaning my previous two responses didn't appear.










First of all, I wanted to say thanks to everyone for the help. As tpenfield and paulm12 said, the pulley hits the gear when the belt is missing. Replacing the belt solved that. At least now if someone else sees the pulley hit the gear, they can find my thread and see the solution 

After fixing the pulley thing, the friction wheel seems to work fine. I'll clean everything and relube anyways, but good to know the part is still useable.

I fixed the spring for the "clutch" return. Basically I took it out, heated it with a propane torch until it was red, stretched it slightly and reformed the broken end, and then reinstalled. Works fine now, but I'll probably order another just in case.

After this, I just have to rebuild/replace the carburetor (I'll use the helpful videos that Grunt provided) and perform some rust repair and then the Toro is good to go for it's 33rd winter.

Thank you everyone, I will post some updates as I progress


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## Mike C. (Jan 28, 2016)

paulm12 said:


> I have noticed that with the drive mechanism spring released the gears can contact the pulley. Makes a noise when moving the machine around. see pics, machine is up on its housing, one is when I hold the parts together. Also see wear marks on pulley. This will be resolved with reattaching the spring.
> .


Drive belt should be 3/8 x 29".Is the belt a bit too long?


Toro part number 37-9090.


I have a Toro 521,too.I put a Harbor Freight Greyhound 6.5hp OHV engine on it 7 or 8 years ago.Much quieter and better on gas than the old Tecumseh and still starts on the first or second pull every time.Honestly,the old engine served me (and the original owner)well until two large,deep grooves mysteriously showed up in the cylinder wall resulting in low compression.


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