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Discussion Starter #1
I have a old 3 hp briggs engine on my snow hound snowblower. It likes to shear fly wheel keys for some reason!!!!:unknown: The flywheel is tight any help is appreciated!
 

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At what point is the key shearing? While it's running? At start-up? When you engage the auger?




Back in the days when I was repairing lawn mowers for a living I remember that keys only sheared for a couple of reasons - 1) you hit something with the mower blade, or 2) the flywheel wasn't tight enough.

There should be a "compression washer" between the flywheel and the nut (or starter clutch) that's holding the flywheel on to the shaft. If you've just got a regular washer, you might not be getting it tight enough.

Is your flywheel just held on with a nut, or does it have the starter clutch on the top? If it has the starter clutch, do you have the special wrench for it?

Whatever you do, please don't be tempted to put a steel key in the slot in place of the aluminium one!!
 

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I don't have a washer between the starter clutch and the fly wheel.... No I do not have a special wrench. But have been getting it pretty tight. Generally I can get it started and running for a few seconds before it shears. yes I had a aluminum key
 

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I think we found your problems then! :good2:

Google "Jack's Small Engines" and put in the model number for your engine. The washer is probably a few bucks. The "Starter Clutch Tool" is about $9.00. Get a few spare timing keys too.

You can use an impact wrench on the starter clutch if you have the tool. Without the tool it's next to impossible to tighten it enough. I've seen plenty of those starter clutches with broken tabs on them where a home mechanic tried to use a hammer on the tabs to loosen or tighten them.

Good luck!

Sent from my SM-G900V using Tapatalk
 

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I looked it up and it shows a regular washer......
 

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RJ, Listen to Mark! Although the parts "show" a regular washer, round outside with a hole, it could be the "compression washer" Mark mentioned. These are also called Belleville, conical, and spring washers. They are cup shape and supply additional pressure when tightened. Install cup-side down against flywheel, and tightening will flatten the washer. Bob
 

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Discussion Starter #7

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"Belleville Washers"!! THANKS for jogging my memory. It seems like a long time ago since I worked on those engines. Oh, wait - 1978-1985 WAS a long time ago!! :laugh:

Here's a link to Amazon that reinforces that it's not a regular washer. Amazon.com : Briggs and Stratton 7024467SM Washer, Belleville - 1-3/4 Outdoor

The behavior you describe totally points to the flywheel not being tight enough. Every time the engine hits a compression stroke, it's jarring the crankshaft putting pressure on that key. The key distorts a bit each time. After several times, it's distorted enough that the magnets on the flywheel are in time any more.

Again, get the starter clutch wrench. You're fighting a losing battle without it. Also, if you don't have an impact wrench to use with the clutch wrench, also spend the money to get the "flywheel holder". You won't be able to hold the flywheel tight enough by hand and you sure don't want to stick a screwdriver in the flywheel vanes to try and hold it.

If you have a local small engine shop and a way to transport the snow blower, stop in and see if they'll tighten it all up for you. It will take them all of about 2 minutes to do if you have everything exposed and you're putting all the sheet metal back on yourself. There's a good chance they'll have the washer in stock as well.
 

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there is nothing cupped about this washer. I must have looked up the wrong one. Briggs and Stratton 690582 Washer - Jacks Small Engines
Hard to see any "cupping" in the picture, but.... If you Google "Briggs 690582" and go to the Amazon link and you'll see that 690582 replaces washer 225136 (and several others). Google "Briggs 225136" and you'll see some images that show the original B&S packaging labeling it as "Washer-Flywheel" indicating that there's something special about the washer. If you Google "Briggs 225136 Belleville" you'll get some other good links, but I think that this one shows it best....
http://www.barrettsmallengine.com/ayp/partslist/9178A99.pdf

Page 1 of the PDF shows that the flywheel washer is item 75. Scroll down page 2 to Item 75 and you'll see that it's part number 225136 described as "Washer, Spring". That means that it's not flat. Buy the right washer - it's $2.28. Properly tighten down the flywheel as I described and, I'm willing to bet you a cup of coffee, you won't have any more problems with this. :good2:
 
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