carburetor question-Craftsman Mower

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  #1  
Old 10-16-08, 12:29 PM
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carburetor question-Craftsman Mower

Briggs & Stratton specs:
Model 10M902
Type 0489 E1
Code 08090755

Hello all,

I'm having the hardest time with this mower. Bought maybe 3 years ago. It's craftsman 4.75hp pushmower, the engine is B&S.

The problem i'm having is that it will start for about 4 seconds then die. Then I will prime it again. It will start for 4 seconds then die.

So far I have cleaned the element (in hot water and soap)
I have also taken a look at the spark plug and it was fouled.
With the spark plug removed, I pulled the starter rope a few times to remove the excess oil from the cylinder.
Then i put a new spark plug in.
I also cleaned out the muffler using first some carb cleaner, then soaking it in hot water and soap.
The oil level was a little overfilled so i took some out, now it's at the appropriate level.
Keep in mind I have fresh gas in the tank which was bought a few days ago.

I just don't get it! It was running fine last week.
I am wondering whether i should clean out the carburetor, and if so, can anyone give me some tips on removing it?

There are 5 phillips screws that attach it to the gas tank. I loosened those. Anything else? I saw a spring, i'm not sure if i should remove the spring. and after removing the 5 screws should the carburetor come right out? In the picture below, I removed the air filter (element) to show you the carburetor. By looking at it, it looks like the bowl-type, but i'm not sure.



any advice?
-Lora
 

Last edited by mowerFL; 10-16-08 at 12:55 PM.
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  #2  
Old 10-16-08, 02:04 PM
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It was running fine last week, now it won't. First I would try to start it wit the gas cap loose. If it starts & runs, then the vent holes in the cap are plugged. If that doesn't work, I would siphon out the gas into a clear container to see if you have water in the tank. If you do have water in the tank, then I would get some Isopropel dry gas and add 2 oz per gallon to the gas(for the sixe of your tank, it would only need 1 oz.).
 
  #3  
Old 10-16-08, 03:13 PM
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I know for sure that the holes in the gas cap are not blocked. I tilted the lawn mower and some gas spilled out the cap through those tiny holes.

I also removed all the gas from the mower and put it in a clear container. I didn't see any water floating.

hmm.

if you'd like a look, here might be a better picture

 

Last edited by mowerFL; 10-16-08 at 03:30 PM.
  #4  
Old 10-16-08, 05:27 PM
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To remove the carburetor you will need to remove the fuel tank.

There are two bolts holding the tank on the engine, one just to the right of the fuel cap, and the other on the front side, just below where the spring is attached.

Once these bolts are removed then pull slightly out on the fuel tank to disengage it from the intake tube, once the carburetor is off the intake tube you will need to unhook the throttle linkage from the carburetor, it's just a "Z" bend. When the tank and carburetor are off of the engine then the carburetor can be removed from the tank.

Pay attention when you remove the tank and carburetor from the engine as sometimes the "O-Ring" seal in the end of the carburetor will come off and stay on the intake tube. If this happens, take it off of the intake tube and reinstall in the carburetor, there is a plastic retaining ring that holds the "O-Ring" in the carburetor, be sure to snap it back in front of the "O-Ring".

You can clean out the tank and carburetor, I would recommend replacing the gasket and diaphragm assembly (Briggs # 795083) as this is a likely cause of your problem.
 
  #5  
Old 10-16-08, 08:30 PM
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Thank you for the detailed reply 30YearTech. I printed out your instructions and went at it.

I took the fuel tank off, removed the carburetor and honestly i didn't see much gunk or buildup. I intended on spraying the carburetor with carb cleaner, however i noticed the carburetor was plastic, and i didn't think you were supposed to use carb cleaner on plastic. I took a few pictures hoping you would take a look to give me some pointers. To see the slideshow of pictures i took, click on the mower picture below.



Now as for ordering the 2 parts: gasket and diaphragm.
What is the easiest, and cheapest way for me to do that.
I usually order my parts from Autozone or Napa, but whats the best way to get lawnmower parts?
 
  #6  
Old 10-16-08, 08:37 PM
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Any local small engine shop should have the gasket/diaphragm kit for this for a few bucks.
 
  #7  
Old 10-16-08, 08:39 PM
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There are numerous websites that sell parts for Briggs engines. I would go to the Briggs website http://briggsandstratton.via.infonow.net/locator/
plug in your zip code and find a local dealer and just purchase the part number I listed from them.

You can use carburetor spray cleaner on the carburetor with no ill effects, it may not be a problem with dirt, if the diaphragm had a leak it could cause the problem you described. But since you have the carburetor down, spraying it out certainly will not hurt anything.
 
  #8  
Old 10-17-08, 01:17 PM
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I wanted to ask, what would cause this problem of the diaphragm leaking?

The reason I ask is because a few weeks ago the lawn mower was running fine, and my uncle came over to borrow it for his yard, and brought it back and it wouldn't start up...

I noticed that he primes it 8 times instead of the usual 3 times.
Is that okay? or would that have caused the spark plug to foul and put so much oil in the engine?
 
  #9  
Old 10-17-08, 10:32 PM
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Priming it 8 times shouldn't have hurt the diaphragm. Too much oil wouldn't either. Sometimes parts, especially thin rubber diaphragms, just wear out or go bad. It's common on that engine for the diaphragm to give trouble once in a while.
 
  #10  
Old 10-18-08, 10:13 AM
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MowerFL;
In my area you can get the part you need a Lowes in the garden equipment area it is a kit number 5083 and has the diaphram, gasket, screen and diaphram spring for $2.98 so if you have a Lowes in your area it could be worth a visit. Since 30Year has the tank off I will add some additional info that I usually post for this problem, it is only to add to 30Years instructions.

Briggs Carb
You need to install a new diaphram kit, it is Briggs part # 795083 or old # 495770 also Lowe's has a kit #5083 which has the same parts.

Here we go;
Remove air cleaner, there are 2 bolts that hold things together, one on the front of the tank 3/8" and one into the block 1/2", remove these bolts, now "slowly" slide the carb/tank off the intake tube and breather tube, now tilt the tank in to release the throttle linkage and waalaa the carb/tank is removed. Remove the 5 screws from the carb/tank remove carb(don't loose the spring) now spray all holes, cracks and crevases in both the carb and tank surface with brake parts cleaner, remove the main screen(looks like a thimble) with a small screwdriver pry out the main jet(carefully,don't destroy the little O ring) and clean it, reinstall the jet, it can be difficult some times to get it to snap back in place(I use the rounded end of a screwdriver handle). Remove and clean the fuel pickup stem. Clean any junk/rust from the tank. Install the diaphram on the tank then the gasket(no goo or sealer) now carefully replace the carb(the spring will try to misalign the diaphram), tighten all screws a little at a time so as not to crimp the diaphram until they are all tight. Install the carb/tank in reverse order and you are done. If I missed something one of the real mechanics will correct me. Have a good one. Geo
 

Last edited by geogrubb; 10-18-08 at 10:30 AM.
  #11  
Old 10-21-08, 02:28 PM
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Thank you geogrubb, I will head out to Lowes today to get the kit. Should i clean the thimble and jet with carb cleaner? You said to "clean" them, but i'm not sure if i should use the carb cleaner on it.


Originally Posted by geogrubb View Post
MowerFL;
In my area you can get the part you need a Lowes in the garden equipment area it is a kit number 5083 and has the diaphram, gasket, screen and diaphram spring for $2.98 so if you have a Lowes in your area it could be worth a visit. Since 30Year has the tank off I will add some additional info that I usually post for this problem, it is only to add to 30Years instructions.

Briggs Carb
You need to install a new diaphram kit, it is Briggs part # 795083 or old # 495770 also Lowe's has a kit #5083 which has the same parts.

Here we go;
Remove air cleaner, there are 2 bolts that hold things together, one on the front of the tank 3/8" and one into the block 1/2", remove these bolts, now "slowly" slide the carb/tank off the intake tube and breather tube, now tilt the tank in to release the throttle linkage and waalaa the carb/tank is removed. Remove the 5 screws from the carb/tank remove carb(don't loose the spring) now spray all holes, cracks and crevases in both the carb and tank surface with brake parts cleaner, remove the main screen(looks like a thimble) with a small screwdriver pry out the main jet(carefully,don't destroy the little O ring) and clean it, reinstall the jet, it can be difficult some times to get it to snap back in place(I use the rounded end of a screwdriver handle). Remove and clean the fuel pickup stem. Clean any junk/rust from the tank. Install the diaphram on the tank then the gasket(no goo or sealer) now carefully replace the carb(the spring will try to misalign the diaphram), tighten all screws a little at a time so as not to crimp the diaphram until they are all tight. Install the carb/tank in reverse order and you are done. If I missed something one of the real mechanics will correct me. Have a good one. Geo
 
  #12  
Old 10-21-08, 10:49 PM
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You can use the carb cleaner on them.
 
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