briggs and stratton amreture magneto

natefg2

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I have a mower I am trying to revive and get running. I bought it running but after using it i found it was running it seemed full throttle and shaking like crazy that it hurt my hands to use. In all the shaking I lost some screws out of the flywheel cover and the coil wire jumped out of its groove and was severed by the cover. So in order to try to fix the original throttle issue I had to replace the coil. I ordered a new one but I don't think i have the right part. The dead one had just the coil wire and tab to clip on the ground wire. The new one I have has the coil wire, a black wire like the ground and a third bare copper wire. I tried to install what I had and couldn't get it to run. I don't think it is even giving spark. What I want to know is if there is a way to get the new part that seems to be wrong to work anyway before I spend more money on the correct part. My motor is the 10t502 0457 b1.
 

ILENGINE

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From your description it sounds like you have the module for the point igntion system. There is no way to retrofit your engine for that type of module. You will need the electronic ignition module for your engine. The seond thing is from your description of the vibration makes me wonder if the mower have a bent crankshaft.
 

natefg2

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I bought it on craigslist as I didn't have the money for a new one at the time. When I went to get it we started it and it didn't seem that bad but once I got it home to use it seemed different but I didn't think much of it at the time. I came with a new gator blade. What my theory is, is when loading it in and out of my car i may have moved the governor plate from where it was when I tested it out. I didn't come to this thought until I had already cut the coil wire. So until I get the new magneto on and working I cannot test that idea out. I'm hoping i can save it because I like the deck better than what im using now which is just a plain small weedeater mower with side discharge only... I'm glad you knew what I was talking about without photos of the parts in question. It did really just shake itself to pieces. Is it sounding like it might just be better to scrap it or worth fixing?
 

ILENGINE

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While looking under the deck, turn the blade by hand and see if the mounting bolt seems to stay in one place or moves side to side. Another way to check it is pick a spot on the deck next to the blade, and then turn the blade half a turn, and see if the other end lines up with that same spot. With a known straight blade, any up or down deviation in position means the crankshaft is bent.

If bent you may be better off just scrapping the mower. There may people out there that will tell you how to straighten the crank, or may even have the tool to straighten the crank. There is risk of cracking the crankshaft, which may fail at a later time resulting in personal injury or death. That is the reason repair shops don't do straightening any more.
 

natefg2

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I'll check it later today and see what I find. I guess that will give me my answer on weather to fix it or not. I looked up some videos on YouTube of bent shafts on mowers but I'm not sure that was the issue .
 

Mower Doctor 78006

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Lay the mower on it's side oil dipstick down, not on carb side. Rotate blade by hand and look for wobble. The engine could have a broken blade adapter, it could have a bent crank, it could have a bent blade ect. The blade could be loose. All those things are possible. It could be missing the governor springs, they could be bent. For the mower to shake and run full ungoverned Rpm and rattle bolts loose there something really wrong. It could also have snapped engine mounting bolts.
 

Mower Doctor 78006

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In all my years of running and repairing mowers I have never had a coil loosen up and get destroyed!! Somebody had to be playing with that engine and messed it up. I think bolts were never tightened down. On that style engine if the governor vane isn't mounted with a washer under in before bolting coil down it will bind in wide open position. Iam sure the engine was screaming!! I live in the San Antonio,Tx area. I have good used briggs Classic coil's. That's the style engine you have.
 

natefg2

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So in your opinion you dont think the motor running full throttle would cause those kind of vibrations?
 

Mower Doctor 78006

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Not to the point of shaking the bolts loose!! They were loose already Iam sure. It will cause some. I bet your problem is in the blade, blade adapter, or crank being bent. The full ungoverned issue still needs fixed............... But that won't cause the engine to shake to death!! Look at all engine mounting bolts. Then blade look for loose wobble, bad blade adapter, blade bolt not tight ect.

So in your opinion you dont think the motor running full throttle would cause those kind of vibrations?
 

natefg2

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So I tipped the mower over and took off the blade and everything else down to the shaft, pulled the cord and it looks like the shaft is bent slightly. I couldn't really tell just by spinning the blade so I used the cord to turn it. Then I noticed some wobble in the blade adaptor. So to rule all those parts out I stripped it down to the shaft and saw the slight wobble. So I guess it may not be worth fixing. The motor mounts and bolts look good and tight. On top of the ignition coil it looks like it will need a new pull cord, and probably carb work because something is slowly seeping gas onto the deck from sitting almost a year. I suspect somebody was messing with it before me as well.
 
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