flywheel key Question(What I found!)

[GWGAllisfan 159]

What would be the efeect/harm in running an engine with a potential sheared/ bent flywheel key? http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=77810 As seen in the above link, I have a 23D that won't run on the magneto, but runs fine on a coil. My concern is if the key is bad, will this allow flywheel to slip on the crank?

[HubbardRA 19]

From my experience, when the key shears the flywheel will spin on the shaft when starting.

[BLT 725]

My experiences are this, when I shear a key on my lawn mower, it is the result of a surveyor's stake, well casing, or anything else defending its honor causing my engine to stop abruptly and the mag catching up, hence sheared key. On my belt driven mowers, the belt does the cushioning so no sheared key. When I have had the mag off and didn't torque it up enough I have got partially or all sheared keys. So my guess is that at some point in time your mag (flywheel) will free spin when you least expect it.

[andrewk 0]

The key is there to index the flywheel so that the timing is correct to the mag. The torque of the nut (or bolt) will hold the flywheel in place, but if the key is sheared, the crank will slip on the flywheel, and will probably eventually ruin the flywheel. I don't think you would run it long if it was slipping though, since the timing would be way off. So the consequence will be a hard starting, poor running, backfiring engine. If you engine runs on a coil, could it be possible that the mag is bad? All you need to do to check is pull the fastener on the flywheel, and you will be able to see the key. It's worth checking out in my opinion.

[firefoxz1 4]

Well I don't think much if you run on an auto coil except a little scoring of the mating surfaces (the taper) unless it really loosens up. If the flywheel is balanced to the crank, as a counterweight, you may end up throwing out bearings in the engine if not properly aligned. I do not think these are set-up that way but am unsure, I think the flywheels are balanced to themselves.

[Ronald Hribar 127]

Seems to me, that you are going thru a lot of extra work and expense to avoid pulling the motor and replacing a $1.00 key. At the same time , you can check on mag. Also you can make sure cooling fins are free of debris. And when torqueing flywheel down, make sure that it is to specs.

[GWGAllisfan 159]

I have a new flywheel key on order, no one around here stocked a 23D key, just trying to understand what the effect would be. I'd already decided to pull it to check it and the coil. I admit I didn't want to pull the motor, just laziness on my part. I did the auto coil thing to confirm it was an ignition problem. Thanks for all the advice. myabe they'll be time this weekend to see what's wrong.

[GWGAllisfan 159]

here's what I found.
[img]/club2/attach/GWGAllisfan/100_1097_key.jpg[/img]
Picture is a little unclear, but the key wasn't sheared, or even bent. It had no spark at all when cranked after the shroud removal. It had had a weak spark in previous attempt. I even jumper wired the magneto to points to make sure the connection weren't bad.:( Maybe I'll just paint one of my spare 243431's and put it in it for now.

[Ronald Hribar 127]

I can not tell much from picture. But looks rusty or dirty. I would make sure mag is clean and shiny and the same for the flywheel. And check clearance between flywheel and mag. The Mag could be bad. Then you can decide whether you want it original or change it to toliet ignition "which works very well"

[perry 1]

you could have that engine on the bensh in about 15 min.{w/air} now gettin the fly whell off is another story. [url]http://s97.photobucket.com/albums/l226/perry71/?action=view¤t=march07sim101-1.flv[/url]