test lawnmower coil
Posted by mitchell under Lawn Mower Repair
Small engine coils rarely go bad or fail to function on single cylinder engines,although twin cylinder engines seem to have more of a prob
Published on Wednesday 8th of February 2012 02:32:36 PM
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This past summer,I ran across some interesting thingsconcerning carbs and cams in Briggs an Strattonengines.First of all a customer brought a riding mower in with a12 hp Engine the complaint was that it was running wideopen whenever it was fired up.I immediately checked allof the linkages going to the carb,governor linkages andso forth.They checked out fineand if I had not seen this before, I would have beenstumped.What had happened and apparently was a defect thatBriggs was having on some of these engines.Thescrews that hold the butterfly in the carburetor in placehad vibrated out and were sucked into the engine,passed the valves, into the head and either they willimbede themselves into the soft aluminum head orpiston, or pass out the exhaust side.AT either rate theengine runs wide open because the butterfly cannotcontrol the gas flow .I had one that had sucked thebutterfly into the manifold, intake manifold.I have sawthis happen to several 12 and 14 hp engines, so I know ithas to be a defect of not putting enough loctite on thebutterfly screwsSecondly, a customer brought a 15 hp intek, Briggs anstratton in.The symptoms were,it would fire up and runon idle, but would not idle up.I checked the carb, andimmediately after finding it to be o.k. Proceeded toadjust the valves,being a overhead valve engine. Thatdone, the symptoms were no better.What washappening was the intake valve was letting fuel in, butthe exhaust valve was not staying open long enough tolet exhaust out,so Iput exhaust valve way out oftolerances to see what would happen, nochange.Immediately the possibility of a bad cam cameinto mind,but the engine was no more than two yearsold, then I saw made or assembled in Mexico on theflywheel cap.I pulled the engine, disassembled thebottom crankcase, pulled the cam and wala, one of thelobes was almost completely gone.The exhaust lobe tobe exact. I did this to two 15 hp inteks last season,soapparently there is a defect in some of the cams in thenewer engines,possibly its been solved by now.Also didthis on a 17 hp engine.Note; the replacement cams wereof much better quality.Hope these snippets of info will help you,if you runacross these type of things in the future.
Posted by under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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Carburetor solonoids have replaced the fuel bowl nut on a lot of todays engines,from kohler,briggs tecumseh, kawasaki, onan and most of the others.The purpose is to shut fuel off from intake manifold when ignition key is switched to off position.The carb solonoid consists of two wires,a power wire and a ground wire.The solonoid itself controls a pin that retracts from the bottom of the carb fuel jet when ignition is turned on allowing fuel into carb and intake manifold,sometimes you can hear it click right before you turn ignition to engage starter.If you dont hear a click and engine wont start, then the solonoid could be bad.One way to check is to disconnect wires from bottom of solonoid, since they ususally plug into it, it is relatively simple to remove them and then unscrew solonoid from bottom of bowl, it helps if you discconnect fuel line from carb first to avoid gas spillage,after you have removed solonoid, plug wires back in to it and switch ignition on,you should see pin retract, if you dont then the solonoid is bad.To fix replace solonoid, or snip pin off even with threads and re insert solonoid as a bypass trick.One important note is that if you have a completely discharged battery and you jump engine off and take cables off the engine will possibly go dead, since solonoid needs electricity to work.For somephotos go to http://pass.smallenginetrblshtng.com and see safety switches.
Posted by under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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So you have just graduated small engine repair school,or just would like to get into the business.Well first of all save some of those advertising dollars,if your the new kid on the block.Word of mouth goes a long way in any business.All you have to do to get in the business assuming your good at repair is to take some of those advertising dollars and scour the area you live in for mowers setting up in peoples yards, you can see them by driving by a lot of times.Stop and ask them what they plan on doing with them.Dont tell them you know how to work on them, nine times out of ten they will get rid of them for a little of nothing.Next after you have aquired several mowers.OH,and try to get the ones that are complete, not the ones torn apart with pieces everywhere.Now you will find, you will have to buy batteries, fix tires, replace solonoids and whatever simple things that stopped them from working in the first place,but now importantly they are yours.Fix them and sell them through your local paperas used mowers.You can double your money this way a lot of times.Also as you sell one, you agree to repair it for the person buying,should anything go wrong.Trust me, they will spread the word,plus you will be making money and getting free advertising this way.Also people will see you workingon these mowers you have aquired and if you live in a high traffic area where a lot of people see you.People will stop by and ask you if you work on small engines without any type of sign advertising it.I know of an individual who graduated from repair school and actually was a pretty good mechanic,bought a small building, put an ad in the paper and waitedHe was closed up in six months working in a factory,simply because the school didnt give any marketing advice as above.Word of mouth is the most powerful advertising there is.If you follow the above advice, you will find eventually that you want have time to scour the area for potential profit selling used mowers you fix,they will be bringing them to you.
Posted by under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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briggs an stranton
Posted by mitchell under Lawn Mower Repair
Todays small briggs an stranton engines have a pull rope mechanism a lot simpler than the old style engines of yesteryear.Flywheel cap mu
Published on Wednesday 8th of February 2012 02:32:36 PM
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Mower blades are one of the most important parts of your lawn mower,since thats the whole purpose of the mower is to cutt.So its only natural that they are commonly overlooked until they give problems.Uneven cutts or streaks left in the middle of a two blade cutt such as a 42 inch cutt.
Posted by By middle summer blades will need to be changed or sharpened most of the time,usually you can take them off and sharpen with a bench grinder or a side hand held grinder,which is a wise investment since it will pay for itself over time by saving at least one set of blades a year by sharpening.There are several types of blades, mulching blades,gator blades, wing type blades.Mulching blades are suppossed to cutt and recutt grass clippings, leaving a fine residue behind of grass clippings. under Lawn Mower RepairOne thing to remember when installing your new blades on, craftsman, poulan, husqvarna,or any mower with a star type hole in the middle is to make sur
Published on Wednesday 8th of February 2012 02:32:36 PM
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Small engine coils rarely go bad or fail to function on single cylinder engines,although twin cylinder engines seem to have more of a problem, especially briggs.The flywheel has a magnet attached to it in a certain spot and as it passes by the coil,it causes the coil to charge and send a spark to the spark plug.There are no power wires going to the coil.The only wire on todays engines attached to it besides the spark plug wire is a ground wire that is attached underneath coil and it runs through usually a safety switch circuit on lawnmowers or a cuttoff switch on other applications.However if a power wire gets attached to this ground circuit by mistake it will blow the coil.Ihave seen this before, also it will smoke or burn the hot wire that is attached by mistake.Older briggs and tecumseh have a set of points and condenser that are located underneath flywheel and usually that was a yearly chore to replace points and condenser, but todays engines use an electronic coil that does away with the points and condenser.You also can replace old style coil that has points with electronic coil, by simply bolting it on.TROUBLESHOOTING COIL is simple by disconnecting ground wire, which is usually black coming from coil,pull plug out, spin engine and watch for spark, no spark, bad coil, good spark, good coil assuming spark plug is good.You can bypass safety switches with this method also,engine wont shut off until you connect wire back though.Briggs coils from one engine to another as far as horsepower wise usually wont interchange, it all depends on the size of flywheel in bigger horsepower engines.A SIGN of a coil going out will be that the engine will run until it gets hot and then shutdown and when it cools will fire back up and do the same thing,do the above test when its hot to check for sure that it is the coil failing.Coil gap is .010 between flywheel and coil.
Posted by Small engine wiring is relatively simple from 3hp to 20 hp.Take for example the old style briggs 12 hp without overhead valves.There are usually two wires coming from underneath the flywheel cover or cap,one is the charging wire, which comes from the alternator and it is located underneath the flywheel, it charges the battery thru one of the wires coming from underneath the flywheel cover.The other wire usually a black wire goes to the coil as a ground wire and serves to shut engine down when you turn key off, it also winds its way through your safety switches.These are actually the only two wires on a 12 hp, unless it has a fuel shutoff solonoid underneath the bowl of the carb, which most of todays engines have.The latest engines are mostly overhead valve with this fuel shutoff solonoid on the bowl,which is an added two wires to the engine,so now their are four instead of two.The fuel shut off solonoid will have usually a grey and black wire going to it, the black is a ground and the grey is a hot wire, when ignition is turned on.I f your battery is dead and you try to jump engine off, most likely it will run until you take jumper cables away,because the fuel shutoff solonoid needs a good battery to operate.I MYSELF usually by pass this solonoid by unscrewing it from the carb and snipping the pin off even with threads, when I FIND IT BAD.It is a shade tree method of getting out of spending 30 to 40 bucks for a solonoid.I ALSO INSTALL A cuttoff valve between tank and carb so I CAN CUTT FUEL OFF FROM ENGINE WHEN NOT RUNNING.In actuality a lot of troubleshooting can be performed,by disconnecting the wire to the coil, or ground wire, not spark plug wire. For instance if your engine spins and does not fire, you can disconnect this wire,and if it fires and cranks it tells you that you have a bad safety switch,since ground wire winds its way through those safety switches.The wiring on a small engine rarely gives any trouble,most of the time its the wiring on the frame of the mower or what its powering.Safety switches are usually the problem associated with not running.TIP;Indication of a bad ignition coil would be, if you disconnect the ground wire talked about above and the plug will not fire with a plug you know is good, is a good indication the coil is bad, also an engine that will run until it gets hot and shuts itself off and the when engine cools, cranks back up is another indication coil is going bad.More information on safety switches can be found in my troubleshooting guide at http://pass smallenginetrblshtng.com under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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A good spring tune-up on your briggs, kohler, honda or tecumseh should involve a oil change, a new sparkplug and draining any of last years gas out and replacing it with fresh fuel.Also it is a good idea to clean the carburetor bowl out, especially if the engine is over two years old, assuming you have a carb bowl type carburetor, which 90 percent of todays engines do.FRESH FUEL, GOOD SPARK AND CLEAN AIR FILTER and you should be on your way to a good start this spring,engine wise.If your 20 or 22 inch walmart special pushmower wont start or wont stay running after your tune-up, its time for a new carb, since briggs is putting plastic carbs on these without any adjustment,about a 21 to 23 dollar replacement item, my troubleshooting guide shows you how to replace, assuming you have a briggs engine, however if you have the sears special with the tecumseh engine, 9 times out of ten it will have some bowl type carb, thats almost neccessary to clean out every season.Actually the nut that holds the bowl on is part of the main jet,and will have two small pin holes that seem to stop up from season to season.I have actually spent ten minutes cleaning the bowl out on one, that the guy had been pulling on all day, ran like a new one, something he could have just as easily done.Check belts, blades, and pulleys for wear.Most of the time an uneven cutt by your mower is worn blades or a bad bearing in a pulley that turns the blades, one side cutts higher than the other.One way to check deck pulley bearings is to grasp the blade from underneath deck and try to move it up and down,there should be no play or very little play in blade,if however you can shake the blade up and down with a lot of play, you need to replace bearings or quill assembly as they are called,since running it this way will give you an uneven cutt, one side higher than the other or leaving a streak of grass in the middle.Batteries, if you get more than a years usuage out of the normal walmart or auto parts store mower batteries consider yourself lucky.One more note on batteries, if you have a electric clutch on your mower to engage the blades, you need a good battery for it to operate properly,you cant just jump the mower off ,have a dead battery and expect the electric clutch to work, the alternator on the small engine will not keep it engaged without a good hot battery.
Posted by under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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Starter problems are common enough on todays engines,although usually its overhead valves out of adjustment instead of starter problems.Especially on briggs engines.Kohler usually if it seems to be the starter then most of the time ,it is the starter.Most briggs and tecumseh starters have brass bushings at the top the armature that wear and cause starter windings to drag against magnets, thus causing a dragging starter so to speak.First before deciding you have a bad starter,check to see if battery is fully charged,if so and starter still turns slow,take the spark plug out and spin the engine, if it spins fast and starter does not get hot to touch,then its possible the valves need adjustment if overhead valves are on your engine.SEE OVERHEAD VALVE ADJUSTMENT IN ARCHIVE SECTION.However if its a kohler, kawasaki, honda or an engine other than briggs or tecumseh, most likely it will be a bad starter.Some starters will collect heat from the engine as the engine runs, they will crank fine cold and when engine builds up heat and you stop engine and then try to restart, they will drag.A simple way to check this is to take a common water hose and wet starter until its cool to the touch and then try to start engine, if it starts you have a bad starter or at least bad brushes inside starter.This test eliminates a bad battery or questionable charging system.If starter fails to turn when you turn key,look for discharged battery, blown fuse between switch or a possible bad safety switch or solonoid.Usually a bad bushing or brushes fail in most small engine starters.Rebuild kits for the various starters can be purchased,but usually its a special order part from most local parts dealers, since they would rather sell a new starter, which is faster and easier to install, but more costly.For more on safety switches and checking safety switches,solonoids see troubleshooting guide.
Posted by under Lawn Mower Repair
Published on Wednesday 8th of February 2012 02:32:36 PM
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In order to reduce the resistance during starting time,various types of compression releases have been used.Hower, none proved entirely satisfactorily until briggs @stratton developed the 'easy spin' starting system.THIS IS SO SIMPLE ONE WONDERS WHY IT WAS NEVER THOUGHT OF BEFORE.The intake lobe on the cam gear is ground with a small ramp which holds the intake open one one thousanth of an inch for a tiny fraction of the compression stroke.
Posted by At slow starting speed the interval of time that the valve is open is relatively long and therefore enough air escapes to noticeably reduce the compression.However,at operating speeds the interval of time is so short that there is practically no escape and therefore horsepower is unimpaired.Actually at 3600rpm the valve is opened for a mere 1/200 of a second.In all other respects the valves operate as in any other four stroke cycle engine.The force required to start an engine is reduced by 50% with easy spin and would be noticed most by a person who has difficulty starting the ordinary engine. under Lawn Mower RepairOne thing we must remember.When testing the compression of an 'easy spin' engine one must spin the flywheel backward in the opposite direction to norm
Published on Wednesday 8th of February 2012 02:32:36 PM
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