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Ok, so I am not an engine guy, but I am learning slowly.

Mower: Murray Select 12.5HP/40"
Model: 405002X8a
Engine: Briggs and Stratton
Model: 28v707
Type: 1113-E1

Well it's kind of old, about 12-13 years maybe? Been running fine for the first month and a half or so of having it out and mowing after winter. Did all the usual things, charged batter, replaced gas (emptied before winter), and added oil and replaced blades. I go to mow last week and about 5 minutes into mowing it just locks up, sounded like when your blade hits something and stops your engine, but I didn't hit anything.

Longer story short, the flywheel was locked up and loosing up the bolt that holds the flywheel down and addig oil slowly loosened it up. So I tightened the bolt back, and now my problem is the flywheel turns way faster than usual and I don't see the carb doing anything or even a spark? I checked the magnet coils and spaced it properly, but not sure what the issue could be. It just spins like crazy and I have searched all over and can't find anyone that has had the same problem. If Any more info is needed, I will gladly oblige. Any help is appreciated, I am sure it is a lost cause, but you never know.

Sounds like maybe a flywheel key sheared. If the flywheel is 'locked up' that would indicate to me the engine as well was 'locked up' and adding oil helped lubricate it enough to free up. I don't see how loosening the flywheel nut would do anything but perhaps break loose the flywheel. Tightening it back down with enough torque shouldn't let the flywheel spin around at all really, even if the key is sheared. No spark could be from either a bad coil or sheared flywheel key, which would also make it kick back and hard to start. I'd venture a guess that when the engine suddenly seized up it sheared the flywheel key right then. Was the engine low on oil?

Ok, I uploaded a quick 10 second video to help, maybe. Thanks.

Loosening up the nut did help break the flywheel free, and yes it was low on oil.

Looks to me like you need to lossen up the flywheel nut and pull the fly wheel and see it the key is good or bad, then if kep is good put it back together being sure key stays in place, one time i had a key slip out the bottom as I put the flywheel back on, tried to start & it back fired, i knew then what had happen, there are a couple tricks you can use to keep the key in place, 1 is a dab of heavy grease, the other is take a center punch and right on the edge of the key way put a light center punch mark on either side of the key way about mid way the key slot, this will make the key tight going in place,

If you motor locked up like You say i am wondering if something os wrong inside, pull the plug & make sure the piston is moving when you trun the fly wheel,

Rat

12 or 13???

buy a new mower

Re: 12 or 13???

redfish9 said:

buy a new mower

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I would definitely do that if it was in my current budget, however some unforseen events have eaten my savings, but I am still trying to sell my house so I have to keep it looking decent.

If I can do anything with this I will have to go to aarons, which is the LAST thing I want to do. I called autozone and o'reileys looking for a flywheel puller and they don't have them, so I guess I will check with lowes and home depot.

Re: 12 or 13???

Personally I don't use a fly wheel puller to get them of I just screw a bolt into the provided holes an pull it off with a claw hammer if you decide to do this then screw the fly wheel bolt in slightly in case it comes of fast you might find tapping it from side to side with a hammer and piece of wood. save money on a puller:smile:

First off thanks for the replies, I appreciate it.

I think I can see what is the flywheel key. I have tried a couple of things to get it off with no luck. The bolts I have don't seem to be long enough to use a hammer with. I will keep googling, but does auto zone have one and they just don't know it?I thought I saw a picture of one on their site, but called and they said no it's just for vehicles. All lawnmower places around here are closed. =(

I can't seem to find the flywheel puller I need, and all other efforts have failed. Anyone have a part or model number for a flywheel puller?

I found this one, will it work?

http://www.amazon.com/Powerbuilt-64...18240&sr=1-3-catcorr&keywords=flywheel+puller

If it is truly spinning because of a bad key, you don't need a puller, it's already loose. If it's not loose, the lack of resistance means much worse, like the connecting rod broken off and just out of the way enough to not hit the crank. From the looks of the video, it doesn't sound like the piston is sliding back and forth like it should.

jrol, i had to have a puller for a Brigs, i ordered it from a online Small Engine place, i will check & see if i can fine the place, when you call them you need all of the Info on your Motor, mine was less than 30 bucks with the shipping

Rat

PS. Don't try driving any thing on your crank shaft end

jrol >< I went back and read you first post, and looked at the vido, I think your motor slung its ROD, Sorry man, but that is what it points to, if so you need to look for a used motor

Rat

LakeRat1 said:

jrol >< I went back and read you first post, and looked at the vido, I think your motor slung its ROD, Sorry man, but that is what it points to, if so you need to look for a used motor

Rat

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Yea, I have been looking for a compatible motor with no luck. I am still going to try to get that wheel off and see if it is possibly the key, but still no luck finding a puller. So a slung rod is what might be causing it to spin so fast?

LakeRat1 said:

jrol, i had to have a puller for a Brigs, i ordered it from a online Small Engine place, i will check & see if i can fine the place, when you call them you need all of the Info on your Motor, mine was less than 30 bucks with the shipping

Rat

PS. Don't try driving any thing on your crank shaft end

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What do you mean driving anything on your crank shaft? I will call briggs tomorrow.

The photo in post #9 definitely shows a sheared key, the slots don't line up. I would try this first.

Called a couple of local lawn mower places and they said it sounds like a rod. And that it is either new mower time or find a cheap good mower that fits my mower. =(

Did you take out the spark plug, look in there while spinning the engine to see if the piston is moving???

HarryHarley said:

Did you take out the spark plug, look in there while spinning the engine to see if the piston is moving???

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I haven't yet, but will as soon as I get home. What's the best case scenario if it is? lol if there is one. Aarons, charges about $110 a month for a total of about $3k payed out. Ugh, I am selling my house so i am going to have to do something.

jrol said:

I can't seem to find the flywheel puller I need, and all other efforts have failed. Anyone have a part or model number for a flywheel puller?

I found this one, will it work?

Powerbuilt 648436 Harmonic Balancer Puller - Amazon.com

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I don't know about that one on Amazon. I ran your engine model and this is the one that is specified for your engine. Flywheel Puller 19203 Order now for same day shipping. 365 day return policy. RepairClinic.com It can ship today if you order it before 8:00 pm Eastern time.

I've been working on mowers for over 30 years and although I have a flywheel puller, I rarely if ever use it. I take a flat punch and lightly hammer around the shaft but be careful not to hit the threads. Put a big screwdriver, or big flat wrench under the flywheel and pull up on it as you hit the top of the crankshaft sticking out the flywheel. be sure to have the flywheel nut on flush with the top so when you hit it with a hammer and be sure to put a piece of wood on top of it first. That should jar the flywheel loose. Might also squirt some JB penetranting oil around the threads before you tap it with the flat punch and hammer. I've always had success with this method. no need to go buy a puller!!

Mini Motors said:

If it is truly spinning because of a bad key, you don't need a puller, it's already loose. If it's not loose, the lack of resistance means much worse, like the connecting rod broken off and just out of the way enough to not hit the crank. From the looks of the video, it doesn't sound like the piston is sliding back and forth like it should.

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I would suggest that you read this post again before buying a flywheel puller. If your flywheel is that loose on the crankshaft you don't need a flywheel puller.

I have tried a couple of methods, and even thought it spins like that it doesn't seem loose at all. Three local repair guys I showed the video to around here said the same thing. It seems like a rod.