Weedeater 500 lawnmower-hit stump, won't start. Fixable or Trash?

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  #1  
Old 05-28-14, 09:04 AM
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Weedeater 500 lawnmower-hit stump, won't start. Fixable or Trash?

Hi everyone,

I hit a stump with this mower, blade is bent on one side and I couldn't pull the starter rope afterwards. It felt like the pulley was binding on something and wouldn't turn, though I was able to pull it a short distance after working with the rope a while.

It has a Briggs & Stratton 500 Series engine/158 cc/5.00 ft. lbs Torque
Model # 10T502-1022-B2

I was hoping someone would know if these engines are repairable or just trash after hitting something. On an older Murray mower I have with a B&S 3.75 Engine, the driveshaft no longer had a shear-pin on the blade/shaft mount spindle. But, I haven't even had a chance to look at the Weedeater mower yet to pull the blade or check the shaft at the flywheel.
I remember on the older lawnmowers, there would be a shear pin with the blade and one mounted with the flywheel that you could replace (That's how long it's been since I had to replace one...)

Thanks for any insight/help you can provide.
greynold99
 
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  #2  
Old 05-28-14, 09:16 AM
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If the crankshaft is bent it is trash, if not it is fixable, remove the spark plug and put a straight blade on it and check it out, I put marks at 4 different points on the deck and turn the blade if both ends of the blade pass the marks at the same height it is ok then replace the flywheel key and you should be ok. Have a good one. Geo
 
  #3  
Old 05-28-14, 09:45 AM
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Hello greynold99

Whenever a stationary object is struck, the blade stops abruptly. However the engines motor shaft often does not. Which is damaging to the blade, which is obvious and to the shear pins. Reason why shear pins etc are there. Usually two. One on the quill where blade is attached to motor shaft and the other on the flywheel.

First, blade must be replaced. A damaged blade will be out of balance at the least.

Secondly, check the motors drive shaft. Hopefully not bent. Plug plug wire. Then slowly crank engine using pull rope and note motor shaft rotation. Should not wobble nor rotate out of balance. Grab with hand an shake it. Should not be any free play nor wobble. Any out of round rotation or wobble of the engines crank shaft, motor is history. Cannot be fixed.

BTW: There should not be an oil on the motor shaft either. Oil would indicate seal is leaking. Motors shaft oil seal leaks? Only option is to replace the oil seal. Requires special tools. May not be a DIY project.

Third, remove engine cover and check the shear key. Should not show any signs of being out of place in relationship to the flywheel or key slot. Any doubts replace it. ***Be advised, removing a flywheel requires a flywheel puller tool. Any attempts to remove it without the correct puller, there are several types, will cause the flywheel to crack or break....

Regards & Good Luck. Sharp Advice.
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During installations of some parts which may not fit exactly perfect, it may be necessary to apply "BRUTE" force in order to compel compliance......... {....just humor folks... }
 
  #4  
Old 05-28-14, 10:54 AM
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Reply to Sharp Advice

Sharp Advice,
Those were my thoughts as well... And basically it sounds as though B&S hasn't completely gone to the 'Throw away and buy new' philosophy.
Once I get a new blade I'll tear into it this weekend.
If only a shear-pin or two is needed, I'm hoping for an easy fix and definitely won't be in as big a hurry in the future.

My backup high-mower is a 25 year old 3.0 hp Murray mower from the defunct GC Murphy Co (No priming bulb and no flywheel brake), that I elevated the frame with Angle and Flat strap steel to mount the wheels 8" high.
Wife calls it my 'Frankenmower' because I've patched it so many times with odd pieces of flat steel, steel door hinges, JB Weld and that 2-part Plumbers epoxy over stainless steel screen to cover the holes and cracks in the frame.
I hated pulling that thing out, because the Weedeater mower is basically 3 priming pumps and one pull to start, but was surprised how easy the Old Guy started after only 4 or 5 pulls and not having been used since last year.
It's also my steep bank mower/on a rope because it's so light compared with lawnmowers today.
I'll sure miss it when it finally gives up the ghost - hate thinking about weed-whacking that bank; just standing up is an exercise in wearing out your boots.
thanks for tips,
greynold99
 
  #5  
Old 06-02-14, 11:30 AM
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Weekend tear down results

Sharp Advice and geogrubb,

I did the tear down this weekend and found that the flywheel key or shear pin had not even been 'sheared' and only had a dent in it from the shaft; but I decided to replace the key anyway. While doing so I checked for any oil leaks around the shaft and if the shaft presented any kind of 'wobble' - but didn't find anything that looked wrong.
Once done, the mower started right up when I got it put back together without a blade.
The big surprise was the next day when I picked up the new blade and the cost was $16.00. Last time I bought a blade, I think it cost about half that.

The only other thing I noticed was that the engine, once started, didn't seem to run at as high an rpm after starting and seemed on the verge of stalling until completely warmed up - which I did by gently toggling the lever mechanism below where the air filter is bolted on. I could gently pull on this lever to get the rpm higher and then, once the engine warmed up - it would run continuously on its own but at a slightly lower rpm than what I remembered.
(I could shut the engine off by toggling this lever in the opposite direction to the far position in that direction. It's kind of like an 'L' or 'V' lever with the spring attached to one of the ends of letter and central pivot point)

There's a small steel coil spring with a long/straight end that fastens onto this lever, that when I pull on it, actuates that lever and I could move it gently to get the engine to run at just a little higher rpm. I'm wondering if that spring got slightly deformed or stretched when I hit the stump and now needs a slight re-adjustment to get back to spec.

Thanks,
greynold99
 
  #6  
Old 06-02-14, 03:42 PM
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When the engine was running did it have the blade on, the blade acts as the flywheel and must be installed for the engine to run properly. Below is a pic of a linkage similar to yours, to increase the speed bend the tab where the spring is attached forward. Have a good one. Geo

 
  #7  
Old 06-03-14, 08:14 AM
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Reply to Geogrubb and update on mower - one more minor issue; blade scrapping

Geogrubb, yeah you're right, there was no blade on when I started it as I just wanted to make sure it would start... Your picture is exactly what I'm seeing and it's that coiled spring with the long straight-end that I thought might need crimped with needle-nose pliers so it's a little tighter - to pull on the throttle a bit more on the opposite end.

When I put the new blade on and started the engine - one pull after 3 priming pumps; I immediately heard the blade banging on the inside of the mower deck.
Flipping it over, it looks like the frame got bent just little from the stump hit - the blade-height as I manually turn it appears to be something less than a 1/4" difference higher on that side where it's scrapping .
On these Weedeater lawnmowers, they have that circular steel guard spot-welded on the inside.
And, I can see a little bit of daylight on the top-front where the engine mounts onto the deck, that's the side where it's scrapping, that I don't see on the rear.
The engine is mounted with 2 bolts on the back and one on the front where it got bent, which is probably why it torqued up because there was only 1 bolt.

Do you have any good ways to get the blade level again. I'm thinking of loosening the 2 rear engine bolts and tightening the front bolt to see if it can be brought down a bit. I suppose I could put a couple of steel washers on the two rear bolts to bring them in alignment with the front bolts misalignment.
I mean you could probably slip a piece of paper between the space but not much more.
Thanks,
greynold99
 
  #8  
Old 06-03-14, 08:30 AM
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First, don't mess with the spring, bend the metal tab it is attached to, that is what it is for. Second, if the deck is bent smack it with a hammer. Have a good one. Geo
 
  #9  
Old 06-03-14, 10:41 AM
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Reply to Geogrubb

I chuckled when I read '...smack (the deck)it with a hammer.'

I was going to put that down as my last alternative for getting the internal circular frame/guard out of way of the blade but thought the experts might poke fun at me for being a neanderthal who shouldn't be working on modern technological engines...

Won't take too long to see if loosening the engine mounting bolts and then re-tightening 'em in a specific way will help or not. And if not, time to pull out my trusty 10 oz ball-peen hammer and placing some strategic strikes where it's rubbing.
Thanks again,
greynold99
 
  #10  
Old 06-04-14, 07:09 AM
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Give the point to the '20 oz. ball peen hammer' solution... Several well placed hits and the mower is running without any further issues.

When I fitted my socket on the engine bolts to loosen them, I found them tightened down so hard and one of the bolt heads was already nearly stripped off...
Thanks for your help,
greynold99
 
  #11  
Old 06-04-14, 08:56 AM
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Success is a wonderful sound. Have a good one. Geo
 
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