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James W
James W, Small Engine Troubleshooting Expert
Category: Small Engine
Satisfied Customers: 3708
Experience:  7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years
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Model #286707-0122-01 - Briggs&stratton Briggs & stratton gas

Customer Question

Model #286707-0122-01 - Briggs&stratton Briggs & stratton gas engine. Ridding lawn mower didn't start for me today. Changed spark plug, cleaned carb, even changed the oil and gave her new gas! She wants to run, but something isn't right! I used it two weeks ago mulching, and is stored in garage. She's old, but reliable. What else can I do to get the mower to start?
Submitted: 5 years ago.
Category: Small Engine
Expert:  James W replied 5 years ago.

James W :

Greetings, My name isXXXXX and I am here to help the best I can. My goal is 100% satisfaction. Let's get started.

James W :

The fact that you made a point of saying that you gave it new gas makes me suspicious that perhaps at one time it did not have new gas in it

James W :

It you ever used gas older than 30 days old, I suspect your problem is still in the carburetor

James W :

did you install a complete carb rebuild kit in when you cleaned it?

James W :

did you soak the carb submerged in carb cleaner?

JACUSTOMER-8dcat78s- :

I ran it low after mulching, but it still had some gas in it. In other words it sat for 2 weeks and I filled it up

JACUSTOMER-8dcat78s- :

no soak, air clean only with a carb cleaner from the store

James W :

did you poke through the tiny holes in the bowl nut and other orifices in the carb with a tiny wire such as found in a bread twist tie

James W :

then blow them out with compressed air?

JACUSTOMER-8dcat78s- :


James W :

If these answers are no, then you are the right track, you just need better instructions

JACUSTOMER-8dcat78s- :

just used a can of air

James W :

OK... Not uncommon, just not quite good enough.. You meant well

James W :

Most likely you have a fuel delivery or fuel quality problem.

As engines sit or get older, fuel that is left in the carburetor can turn to gum and varnish and cause this and other problems.

Also, any gasoline that was left in a gas can for a period of more than 30 days must be discarded because it also has begun to turn to varnish.

Today's gasolines contain MTBE and alcohol. (Ethanol) They turn to "Junk and garbage" very quickly. Alcohol absorbs water. And they call it "Oxygenated fuels! It is the oxygen (and the water) that breaks down the organic compounds in the fuel and turns the gas to "Garbage" (Gum and varnish) The fuels we had just a few years ago had no alcohol in it and would store for longer periods of time before going stale.

Fuel stabilizers do almost nothing to prevent the fuel from going bad with the changes in today's fuels. The whole point of a fuel stabilizer is to form an oily film on the surface of stored gasoline whether in the tank or in a gas can. The idea was to keep oxygen away from the gasoline to prevent breakdown. Since the fuel is already oxygenated, the fuel stabilizer concept is null and void. These fuels start to degrade immediately upon the addition of the ethanol.

Do not buy gas from the "Discount" Stations. The discount stations get a reduced price on gas because they may be buying fuel that is nearly 30 days old already. You may be getting fuel that's nearly stale right from the pump when buying from a discount station. Purchase your fuel from the well-known stations such as Shell, BP, Sonoco, Phillips 66 etc.

More than 70% of all of our repairs in our small engine repair business are due to these same issues. You most likely have dirt, gum, varnish...etc in your carburetor plugging up the small passageways and jets in the carburetor.

The carburetor will need to be cleaned and overhauled as well as the rest of the fuel system.


  • If you plan to do the work yourself, take pictures with your digital camera or at least make a drawing of where all the linkages, gaskets, and component parts go. Correct reassembly is critical.

  • Remove the carburetor from the engine.

  • Remove all of the non-metallic parts since the carburetor cleaner will cause them to be disfigured decompose and plug the carburetor as time goes on.

  • Clean all parts with carburetor cleaner. You will want to SOAK the non metallic parts in a cleaner bath.

  • Blow out all the small holes and passageways with compressed air.

  • Use a tiny stiff wire such as is found on the twist tie on a loaf of bread or on a garbage bag to open all tiny passageways found in the carburetor such as in the screw, nut, or jet holding the bowl of the carburetor on (if it has a bowl). Make sure to look for tiny holes in the bottom and side threads of the bowl nut or nozzle a make sure they are clear with the wire.

  • Wash the carburetor cleaner off of the metal parts by washing them in warm, soapy water then rinsing with clean water.

  • Dry all carburetor parts by blowing it off with compressed air.

  • Make sure that all the passageways are blown dry before reassembling (you do not want water back in the carburetor).

  • Reassemble the carburetor using a NEW carburetor rebuild kit.

  • NOTE: DO NOT TRY TO REASSEMBLE WITHOUT USING A COMPLETE CARBURETOR KIT! You will just end up having to do the job again.

  • Find the Model, type and serial or code numbers off of the engine and take them to your local dealer to get the carburetor repair kit.

  • ALWAYS clean the fuel tank and replace the fuel line when doing this repair or you may have to do it all over again. The inside of the fuel line disintegrates over time and these small pieces of rubber will plug up the carburetor too. Dirt and water from a dirty fuel tank will also plug up the carburetor. If this happens, you will be starting over again from the top.

In an Emergency such as a blizzard where you cannot get out to buy a carburetor kit until the plows come through, or during an emergency power outage and you need a generator running even if it runs poorly, you might try the following if your carburetor is the type that has a bowl. Sometimes this procedure works:

While the carburetor is still mounted to the engine:

  • Pinch the fuel line with a pair of vice grips to stop the fuel from going to the carburetor.

  • Remove the bowl nut (or nozzle from the bottom of the carburetor and let the fuel drain from the bowl.

  • Carefully remove the bowl from the carburetor without letting the needle and seat and float fall out of position (if it does, no big deal, but you will have to reassemble it, which is harder with the carburetor on the unit).

  • Dump all of the Gunk out of the bowl and put the bowl back into position.

  • Use a tiny stiff wire such as is found on the twist tie on a loaf of bread or on a garbage bag to open all tiny holes in the screw, bowl nut, or nozzle that was holding the bowl of the carburetor on (if it has a bowl). Make sure to look for tiny holes in the bottom and side threads of the bowl nut or nozzle a make sure they are clear with the wire.

  • Reassemble and see if you got lucky.

You may be able to finish the job at hand then clean and overhaul the carburetor correctly when you have more time and a new carburetor overhaul kit.

If you don't feel comfortable with these kinds of repairs, or if the carburetor still doesn't work correctly after your attempt, I would suggest sending it to a profession repair shop with a reputation for having friendly, knowledgeable, experienced service technicians. It would be best to take it to someone who has an "Ultra-sonic" cleaning machine. This machine uses a very mild carburetor cleaner in concert with ultrasonic vibrations to get the very small passageways clean. This method is very effective even when traditional methods fail.

There is a New Product that you can try which is guaranteed to work or your money back (per the manufacturer).

It is designed to help clean the carburetor without damaging the diaphragms and rubber parts like regular carburetor cleaner. Click on this site and it will tell you all about it.

The mechanic in a bottle is NOT a conventional carburetor cleaner.

It actually breaks down the varnish into it molecular components and it completely dissolves. It DOE NOT clog up the jets as conventional carburetor cleaners do. Conventional carb cleaners just loosen the varnish and the varnish particles will go into the jets and filters and clog them up.... usually causing much more problems that was originally there. The conventional carb cleaners also will loosen the "GUMK" that has formed in the gas tanks and cause all of that gunk to go through the carburetor as well.


The Mechanic in a BOTTLE is a completely revolutionary product that will in many cases alleviate the need to tear the carburetor down and rebuilt it..... unless there is mechanical wear and tear that would require that parts be replaced.


In addition, the special formula actually is designed to soften and restore the rubber parts in the carburetor such as the needle and seats and gaskets.


Mechanic in a bottle is NOT a cure-all but it can help customer get going in many cases without them having to tear the carburetor apart. If the customer is NOT mechanically inclined, it might save them a trip to the repair shop.


Yes I was very skeptical about this product when I first was introduced to it, but the Distributor demonstrated it and we have tried it on many occasions with terrific results.

Otherwise you will have to clean and rebuild the carburetor.

Please feel free to ask follow-up questions so that we can always arrive at the correct solution. We want you to be 100% satisfied.


James W :

Scroll up to read all the details of the 100 lines I just posted

James W :

All of this assumes that you have good compression and good spark...

James W :

Small engines are pretty simple systems (in theory).

In order to work your engine needs these things

  • Proper compression

  • Proper Gas / Air Mixture with good quality fuel.

  • Proper spark

  • Spark at correct time

  • Proper Lubrication (not required to start and run, but required for it to run very long).

I would check your compression, which must be at least 90PSI, and 110 is desirable.

If the compression tests good with a meter,

I expect you have either a fuel Quality or fuel delivery problem.

But first, we need to know it has spark of good enough quality .

Even if you got it to start and it died, try to start the unit one more time,

Take the spark plug out, reattach the plug to wire to it and ground it to a head bolt. (When you had it out, was it wet or dry)?

If it is dry, we are 99% sure we are on the right track, but we still need to know if you have spark.

Turn unit on and either pull rope or engage electric starter. Look for a bright blue spark and see if you hear it. If it has spark, put a teaspoon of gasoline in the plug hole and reinstall the spark plug.

If the unit tries to start, but only runs until the gas you put in is gone then we need to look at cleaning the carburetor (especially if the plug was dry when you took it out).

Some of these engines have a tendency to sheer flywheel keys. If this happens, you may have no spark, or it may spark at the wrong time because the flywheel has spun on the crankshaft. Eventually, you may want to check this.

You may get lucky and it may start and run. If so, let it. It may "clear its throat" or you may get some work done right now.

JACUSTOMER-8dcat78s- :

I don't have all tools listing above. Im a novice at best when it comes to small engines, but I have spark and combustion....I think! I removed the carb, there is gas at the bottom, I turn the key to start and POOF big orange Flame! What does that mean?

James W :

there is gas at the bottom of the car? that went poof after you took it off?

JACUSTOMER-8dcat78s- :


JACUSTOMER-8dcat78s- :

I took off the carb and turned the key

James W :

If you turned the key with the carb off, and it went poof with a flame, you may ALSO have an intake valve problem where it is not sealiong all the way...

James W :

have you experienced backfiring too?

JACUSTOMER-8dcat78s- :


James W :

when you changed the oil, did it smell like gas?

JACUSTOMER-8dcat78s- :

everytime the mower is turned off actually

JACUSTOMER-8dcat78s- :

not a lot, but it was in the air!

James W :

Sounds as if in addition to the carb still being dirty, the float in the bowl of the casrb is sticking and the gas is not shutting off completely

James W :

your engine can have two diffeent carbs

James W :

one is a Nikki, and the other is a walbro..

James W :

fdo you know whic one you have?

JACUSTOMER-8dcat78s- :

let me go take a look

James W :

compare it to these two diagrams while I go get my soup

James W :

from the microwave.

JACUSTOMER-8dcat78s- :

still here, but I don't have the engine apart. that would take more time

James W :

me too

JACUSTOMER-8dcat78s- :

in general what else to you recommend. It's an old lawn mower and don't want to dump a lot of money into it. Just trying to get through this year and maybe next

James W :

no, other really. other than reclean the carb

James W :

let me know if you need more help

JACUSTOMER-8dcat78s- :

I will. thank you for the directions

James W :

no problem

James W :

I will be notified of your replies and follow ups via email

JACUSTOMER-8dcat78s- :

My carb style is a Nikki. when you say clean, do you have any at home cleaning supplies that would save me a trip to the store?

James W and other Small Engine Specialists are ready to help you
Expert:  James W replied 5 years ago.

This may help know exactly which holes and orifices to clean if this is your carb

Expert:  James W replied 5 years ago.

You need an industrial strength carb cleaner.

Even Gum out is not even close to good enough.

You will need to go to the store to get the carb kit and gaskets anyway, because if you try to clean them with out, you will just be cleaning again.

The carb cleaner must be strong enough to eat everything including plastic which is why you never put the plastic parts in it..

And you limit the exposure of the metal parts to it as well or they will become pitted...

You can likely take the carb into the shop off the mower and get it cleaned for less than $60 labor and possibly as low as $40 labor (plus parts)..

Costs less if it is not mounted..

If you want to try to use the mechanic in a bottle option, you still have to go to the store to get it...

I am sorry there is no Magic bullet for this problem.

Customer: replied 5 years ago.

To be more precise I uncovered that the carb is a walbro! The name was hidden in the build up of gunk :) And not to waste anymore of your time I did google,youtube,etc how to properly clean the right carb holes. I used just the carb spray and cleaned the entire carb mount, float, name it I cleaned it and also took it apart and into the house.... it looks brand new. I didn't replace the seals, or buy a carb kit just yet, bc at this time I just want to narrow down the exact problem. I turn the key and you can hear it fire into the carb. The carb is clean and all the engine does is rev up! I just turn the key and all it does is rev. It just won't turn over and become combustive. If there is anything else I can try at home that would be great! Also, got new gas in a new gas can(1gal to be exact).
I have pressure when I hand turn the engine. So I know I have pressure(unsure if it's enough, but I can hear it) I have a new spark plug, new fuel, a cleaner carb, an oil change. What else can I check?
Expert:  James W replied 5 years ago.
I would pull the spark plug out and examined it and see what color was, that I would also see whether it was dry or wet. I would then take 2 teaspoons of fresh gasoline import that gasoline into the spark plug hole. I was entry for put back in and try to started that way. also while I had the spark plug out I would check to see if I really had spark by grounding the end of the spark plug to the head is looking to gas through the spark plug wire up to it then turn over a look and see if you get a break blue spark. if you don't have spark is possible that he had a problem with the safety switches such as the safety switch of the seat. This could very much keep you from having any start off the entry for starting.