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12 hp Briggs and Stratton model # 284707 1025 e1

Posted by chadnicoletti (My Page) on
Mon, Nov 16, 09 at 18:22

Hello I have a riding mower with a 12 hp briggs engine. I went to get it started the other day and it would turn over and the starter turns the motor but it wont catch on and run . It sputters for maybe 5 seconds. I cleaned out the carb and the fuel tank. The starter goes ata high speed until it makes a whizzing sound. What could this be?


Follow-Up Postings:

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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

Might i say this: If you do not have much mechanical ability, take it to somebody local to have it evaluated, so they can do a "Hands-on" inspection of it!
Your description of the problem leaves us out in left field, as to doing an inspection or follow-up of your problem.
TO WIT:

The starter gear may have broken teeth on the Bendix Drive. The battery may be hooked up backwards--the proper hookup is Red to starter solenoid--black to "ground" which is the tractor frame.
When you cleaned the carburetor, you may have left something unhooked or a part not cleaned out right. Or, not adjusted right!
there are so many things that could be wrong with it, that can't be fixed in a letter! But that said--better check the things i have mentioned. And, better brush up on proper descriptions!


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

My question is: What exactly did the "carb cleaning" procedure consist of? Your problem sounds like the engine is starving for fuel, and that condition might be caused by a few different things (including, but not limited to, a gummed up carburetor. To determined >IF< the problem is related to lack of sufficient fuel, try this test. Air cleaner removed, spray a 1 or 2 second burst of carb spray cleaner directly down the throat of carb (throttle and choke open). Now try to start the engine. If the engine runs on this bit of carb cleaner, and acts like it wants to "GO", (for a moment) and then stops, spray another burst of cleaner in the carb and try again. If you get the same "eager to go" results every time you spray some cleaner down the carb, your engine is suffering from fuel deficiency anemia. So, what was the cleaning you did to the carb? Have you changed the fuel filter? Does this mower have a fuel pump? IF, the engine does not respond "joyfully" to the sprayed carb cleaner, we need to go on to something else besides carb and fuel system. OK, answers to the questions are important in this process.


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

First off thank you for responding to my question which I apologize was very general. I will be more specific now. The battery is hooked up properly. The carb cleaning consisted of takin off the bowl cover and spraying it with carb clean. Spraying carb cleaner in the throat doesnt do anything. I am sure this is a lack of fuel issue but I dont know why. The engine turns over and wants to start badly but wont. I made no changes to the mower and it was working properly a week ago. I also cleaned the fuel tank out and checked the fuel lines for blockage-nothing. Thanks for your help!


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

***"Spraying carb cleaner in the throat doesnt do anything. I am sure this is a LACK OF FUEL issue but I don't know why."***
Read your statement as I have altered it a bit to emphasize part of it and my following explanation.
IF spraying carb cleaner (the type you buy in a spray can) directly into the carb throat DOES NOT cause the engine to start briefly........it IS NOT due to a LACK OF FUEL!!!! The carb spray cleaner IS FUEL...and you have just fed a bit of FUEL to the engine, and it still does not start. 3 things an internal combustion engine requires to run: (1) Fuel (2) Air & compression, counts as a single thing (3) Ignition.
Also, there is some error in your posted model or type number. Plugging what you give into the Briggs website brought back zero results. Looking at some of my other Briggs PDFs I see that (for example) 280707 is a "flat head' engine while 287707 is an overhead valve engine (the only common ground there is 28 CID), so we gotta have the correct info of engine style before we can begin mulling the things that might cause loss of compression (but I'm not saying you have a compression issue "yet").
You also do not state whether you have checked for the presence of spark, so we don't know which direction to turn now that we have reached a "fork in the road" (fuel is behind us now, unless your carb cleaner has been water based dish detergent" :^).


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

you know what gentlemen? For those of you who have great expertise in small engines I applaud you. You have more knowledge about this than I, this I admit. But if your goal is to help people with their problems then why respond to their questions in a manner which can be taken as defaming or hurtful. I may not know all you do about small engines but I dont think it is right for you to act in the spirit of help and post your diagnosis like blatant jerks.
Lets get back to earth gentlemen and try to help with love rather than talk down to people. I hope you feel good about your "help" you have given me


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

***"defaming or hurtful.? blatant jerks? talk down to people? I hope you feel good about your "help" you have given me "***
I don't know if you are addressing me with those barbs or not. Did you see the little :^) icon ? That is my "smilie face" indicating I am grinning a bit, you know, like when you are talking to somebody and sort of kidding around or joking. As far as talking down to someone, HMMMPH! I have no way of knowing at what level of comprehension a poster is fuctioning at, or their experience with engines or whatever, but I try to structure most of my posts to include some basic theory, if it seems to be needed. You might interpret that information as condescending but it is not INTENDED to be, you simply inferred something that was not there. If it helps to put things into context, try to picture it as a conversation where a subject is being discussed where none of the participants know any of the other participants knowledge of the subject matter.
As to helping people: Yep, that's why I visit and contribute to the forum, and I think I have helped some people solve a few problems, as have many other forum members made somebody's day a little brighter in one way or another. So don't interpret my manner of prose as derogatory or condescending! I am trying to provoke thinking and understanding of the technicalities only. I'm not trying to provoke you and I'm not putting anybody down. If you were offended by my remarks and capitalizing of certain words, that is still just a problem of perception. I felt that you were not making the connection to the fact that spray carb cleaner is a highly flammable liquid and that the purpose of spraying it down the throat of the carb was to provide an alternate source of fuel (instead of the gas from the carb) to determine whether a lack of fuel was causing the problem you are having. To shed a bit more light on the use of spray carb cleaner as an alternate fuel, you could remove the carb completely from the engine and lay it on the ground 10 feet away, spray some carb cleaner into the engine intake port, and provided the engine had compression to offer, and a spark from the plug.......the engine would run for a second or 2 just on that bit of fuel. And if you sprayed the cleaner in the right volume, you could keep the engine running on carb cleaner alone, without a carburetor even being part of the equation. You can't expect to get an answer form just a single post in every case, sometimes it requires a lengthy dialogue that may span days or weeks to arrive at a solution. Now, if you like, you can post the correct model and type numbers from the engine so the discussion of your mechanical problem can be continued?


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

284707 1026 e1
this is the model


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

OK, the 6 instead of a 5 made all the difference, even a typo miskey can slip up a person.
284707, flat head engine, means we don't have concerns about rocker arms and pushrods, but there are valves that might be an issue. Let's don't get into the compression aspect right now, more importantly (at this point) is to confirm the presence of spark, or lack of spark. Because the seat of most modern OPE must be occupied before the ignition system will deliver a spark to the plug, make certain the seat is occupied when doing these tests, and because Briggs engines feature a kill switch as part of the throttle controls, be sure the throttle is not in the OFF position while cranking the engine. Have you tried a new spark plug in the engine since your troubles began? If not, it's cheap enough to buy a new one to eliminate a defective spark plug as the culprit, AND it will make the spark test more accurate in any case, OK, remove the spark plug cable from the spark plug and remove the spark plug from the engine. Reconnect the spark plug to the cable and lay the spark plug on a clean, bare, metal surface of the engine or frame where you can observe where the spark jumps the plug air gap. If the spark plug cable has an exposed metal connector instead of a rubber boot, make sure this metal connector is not touching, or near, the metal surface as that could kill the spark. And I must mention that you DO NOT hold this plug in place with your bare hand (unless you like "puffy hair" :^) Crank the engine (or tell your helper to) while watching the gap for a regular spark or arc to occur there when the engine is turning. If you DO NOT see a spark, try a new plug and repeat the test. If the new plug does not produce a spark, we will need to delve into the reasons that might cause a "no spark" condition. Because some of the things that might cause a "no spark, no run" could be related to the electrical configuration of the mower chassis (like seat switches and deck switches), this will be the right time for you to post the technical numbers (Model and serial numbers) from the mower chassis. The technical numbers can often be found under, or near the seat, but they may be located elsewhere, but the chassis numbers WILL NOT be on the engine. They will either be on a decal, or stamped/engraved on a metal data plate. This is something that I would have to do if I were working on your mower "in person", but I can't be there, so...would you do me a favor?
IF, however, the ignition seems to be making nice, regular blue-white sparks (maybe even a nasty sounding "snap"), then we can rule out ignition problems and then move to compression troubles. If the spark is there, but is a pale yellow color and irregular in occurrance (it should spark once per revolution of the engine crankshaft), we may be staring at a weak and defective ignition coil, so the color and rhythm of the spark is as pertinent as the presence of spark. What you describe as a "fast spinning engine" could indicate an engine that is actually attempting to start and run........or it could indicate an engine that has no, or little, compression. So at least post whether you have spark (or no spark) and the color/frequency of spark.
By the way, I'll be out of the house for a while and it may be later this evening before I get back, but I ain't the only one on here, so you may get help from others too. Later.

Here is a link that might be useful: 284707 IPL


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

hey mownie7 im also having the same problem i have lots of sparks got fuel in carb it turn over fine but when i turn it over i get a flame comming out of carb and also muffler maybe i can call u or u can call me to figure this problem out pleas help luc


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

sheared flywheel key ?


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

Luc,

Sheared (or partly sheared key) would be a likley suspect causing the spark to happen before the piston reaches TDC and the valves are closed. Did you wack a rock or root last time out, did the engine backfire on shutdown? Time to remove the tin off the top, get the flywheel nut off and have a look, probably will need to remove the flywheel to really see the key's condition but it's a good start the keyway in the flywheel and crankshaft should be lined up. It does not take much to put the ignition timing off even a few 1000ths of an inch offset in the key is going to move the timing a few degrees. Lucky for us they use a zinc or soft key that shears before it destroys the flywheel or crankshaft and it's a $2 part.

Get the directions specific to your motor before trying to remove the flywheel those cost big bucks and I have broken more than I care to admit by not looking up the exact steps first.


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

hey buzzard i bought the tractor from a guy like that he said it ran fine parked it then when he tryed to start it it did not go do i need to remove flywheel and will i see the key or how will i no if it is bad and how do i line it up again thanks luc


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

Luc,

Well the 'key' is a bit of flat metal, it goes in a slot between the crankshaft and flywheel, once you remove the nut and washer from the top of the flywheel it should be visable. Sounds like you need to go the the local library and get a book on small engines, that will explain the 'key' and show a picture so you know what your looking at. You might just look at the rear axle of your tractor, there is a key their also to connect the axle to the drive wheels when you take off the dust cap.

Now the BIG question is I hope you got a good deal on this as it was not running when you opened your wallet and let the moths out.


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

i paid 50.00 for it i bought one last week with the same problem it was a coil pack so i figure it was the same thing is it a big jo to change it thaks for all your help and how do i line it up again thanks luc


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

$50! well you have a 'small budget' to work with, I think the alternator coil lives under the flywheel, position on the laternator should not make any difference, just putting out AC each pass of the flywheel magnet, not like spark timing. If you can find out which leads are the coil, test them with a voltmeter, it could be either the coil or a bad external regulator.

By all means test first - buy later and don't ruin your bragging rights to the $50 lawn tractor!


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

i buy and resale them this is the only one ive had problem with so far ive sold 22 tractor in yhe mounth of may the cheeper i pay the moore i make thanks for all your help ill look at it and let u no thanks luc


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

One thing that can be done to check the key without actually pulling the flywheel off. Remove the flywheel retainer nut and examine how the keyway slot in the flywheel and the keyway slot in the crankshaft align.

If the 2 keyways are not in perfect alignment, meaning that they are lined up together, the key is sheared.
The tractor you have bought is a likely candidate to suspect a sheared key by the symptoms you describe, but the symptoms may be hinting at some other problems as well.
If this tractor was already giving someone else a fit, they may have given up and just passed the "stuff" on to you.
Flames out carb and muffler probably do suggest a sheared flywheel key. But flywheel keys shear for a reason. The scenario suggested by buzz (hitting tree root or rock with blade) do not usually cause a key to shear if the deck is driven by a belt off the crankshaft, the belt absorbs enough of the stall torque to keep the key intact.
What usually causes the key to shear in lawn mowers is if the flywheel has been removed and re-installed improperly and/or with insufficient torquing of the flywheel retainer nut.
Another thing that can cause key shear (especially if the above applies) is if the carburetor is leaking gas into the engine while the engine is park in storage.
Gas leaks into the engine and fills the cylinder with gas, then when you engage the starter next time you want to use the tractor, the piston comes up and hits the gas and since you cannot compress a liquid, it is as if the piston hit solid steel. The crankshaft stops but the starter tries to keep moving the flywheel, this can sometimes break or bend the key. Especially if the flywheel nut was not tight enough.
And your engine just might have both ingredients (gas leaking carb and undertorqued flywheel nut.
If you find the key sheared, be sure to use a genuine Briggs key to replace it.
I can hook you up with a manual if you want to e-mail me.


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

Mownie,

right on, it's not the fall but the sudden stop!


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RE: 12 hp Briggs and Stratton model # 284707 1025 e1

u can e-mail me that thanks for all your advice here is my e-mail address .... lucsmallengine@hotmail.com ...thanks again luc


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