Nice to see another 421 owner! The 421 is a brute in a small package! The 421 came with a 4 HP engine.
Don’t be afraid of rebuilding your carb yourself! It’s a piece of cake! Order a genuine Tecumseh carb rebuild kit part number 31840. These carbs are really simple to work on. Make sure you remove the Welch plug on the side of the carb. This will give you access to the idle mixing well. Run a small wire through all the holes and passages. Remember to hold the carb with the float bowl pointed down and give the carb a tap with a screw driver BEFORE you reinstall the idle adjustment screw. There is a small rod that needs to be in the down position in the vertical passage the idle mixture screw intersects. Tapping the carb will make the little tod drop. Your OEM carb will work better than a Chinese one. Chinese gaskets are known to leak as you found out. Give it a try!

Hec

 

Small rod? I've rebuilt a few 4hp, and a lot of 5-10hp carbs, I've never seen a rod. Can you post a diagram? Or a video.

Rather than using wire, go to a welding supply, or online, and buy for $2-$3 a tip cleaner, it has ridges for better cleaning of passages.

You can clean a carb taking it apart using spray carb cleaner and be successful however you have greater success if you do 4 things, use a welding tip cleaner, remove the Welch plug on the side by careful drilling a hole then pry it out, soak the disassembled carb in Berrymans Chem-Dip Carburetor and Parts Cleaner, use Berrymans Chem-Dip in an ultrasonic cleaner ($75 at HarborFreight).

 

Yes sir! A small rod. If you take your carb in your hand and turn it upside down then right-side up you can actually hear the rod sliding up and down the vertical passage. That is, if it isn't all gummed up. If you remove the idle air fuel mixture screw and look way down inside the threaded hole, with a flashlight, you can see that rod appear and disappear as you flip the carb over from having the float bowl pointed up or down. If you screw the idle air fuel mixture screw in and the rod is in a position where it is visible you will damage the rod and tip of the air mixture screw. Then the rod will not be able to slide up and down and the result will be an engine that wont idle. I recently rebuilt my 421's adjustable carb. I soaked it in white vinegar for a couple of days and noticed that the little BB that is pressed into the that vertical passage loosened up and fell out. Behind the BB was the little rod. It almost looks like the float pivot pin but about half as long. Grab a 421 or 521 Carb and take a look for yourself! It's in there!


Go to 21:30 in the video. Taryl explains it here. Not many people know about this rod! Taryl calls it a tube but it sure looks and feels like a solid steel rod.

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Hec

 

HeC: I've always heard the "rod" bounce back and forth, never have seen it apart. Maybe I'll cut one open to see.

dwhittle: what is full model and serial of your machine? Should be on a sticker at the rear back housing, model will be 38010 or similar, and serial number follows..

tx

 

Jim

 

Thank you all for all of of this VERY valuable info. Sorry it's taken so long to reply, but I'm a little slow on this computer business (It's an age thing). Anyway, I will order the rebuild kit and give it try. Didn't get a lot of snow here this winter, but will try to get it running for next year. To paulm12, the mod. # is 38010 and the serial # is 0011344. Won't even open the big can of worms about how to store it over the summer , but I use only non-ethanol gas, and run the tank dry with some sta-bil through the carb before storing.
Just one more question please, what are the chances of finding an electric starter for me and the old girl ? I know it was an option when New, but probably not so much anymore.
Thanks again for the help - - - you guys rock !

 

for your 1980 Toro 421:

• parts listing here: Parts – 421 Snowthrower | Toro
• and here with prices: Toro 38010, 421 Snowthrower, 1980 (SN 0000001-0999999) Parts Diagrams
• the carb repair kit is #31840
• the electric starter was #23-3790 you can find used ones in EBay.
• and here is a carb tutorial for similar carb (I think): Disassembly, Cleaning and Repair of Tecumseh Series 1 Carb 632107

 

Thanks paulm12, I'll check these out.

 

Tecumseh part number 33329 will fit 3 to 5 hp motors. Make sure your flywheel gas the ring gear on it.

TECUMSEH SNOWBLOWER ELECTRIC STARTER 33290 WORKS | eBay

 

I have the correct flywheel with a ring gear if you need it. You may also need to tap the 3 holes on the block used to mount the starter. Tap size is 1/4-20. You will also need to remove the starter blank off cover on the pull start housing. Let’s see some pics!

Hec

 

Wow, have to say it again, the knowledge and expertise y'all have is just amazing. Grunt, not familiar with the ring gear , but I assume I would have to remove the rope pull assembly to see that, which I think Hec in Omaha is saying, and yes, some pictures of how this is done would be great. Also, Hec, thanks for the offer on the flywheel and ring gear. If I need it I will take you up on your offer.

I have the correct flywheel with a ring gear if you need it. You may also need to tap the 3 holes on the block used to mount the starter. Tap size is 1/4-20. You will also need to remove the starter blank off cover on the pull start housing. Let’s see some pics!

Hec

 

You may not need to remove the pull start housing off. Try to take a peek behind the sheet metal in the yellow circled area. The two 421’s I have worked on had the ring gear. One had a starter and one did not. Yours is a 1980 model just like mine! The starter housing sheet metal has a portion that is designed to break off and be discarded . Grab the piece with pliers and bend it back and forth and it will snap off. Once that piece is removed, the electric starter can be installed. The piece needing to be removed covers up the flywheel ring gear which the electric starters drive gear has to engage with.

Hec

Starter Housing without ring gear access cover snapped off

Backside view

Flywheel with ring gear.