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my lawn mower sounds less power, running at almost idle speed when cut grass.


wen831's Avatar
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07-18-12, 10:13 AM   #1  
my lawn mower sounds less power, running at almost idle speed when cut grass.

Since last week, my lawn mower sounds working iat idle status, no enough power any more. The gasoling engine is easy to start and runs in full speed if I did not begin to cut grass. When I do cut grass, the engine looks staying at similar idle speed, no full power and eat gasoline 50% fast. One and half year ago, my old mower had same problem, so I bought this new one. Now, same status happens again. Any idea?

Thanks

 
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07-18-12, 11:00 AM   #2  
So, the engine starts fine and runs at full rpm but when you start cutting grass the engine bogs/slows down? If you stop pushing the mower forward into uncut grass does it speed back up?

 
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07-18-12, 01:29 PM   #3  
Have you changed or at least checked the spark plug? Is it stored under cover, or left outside?


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07-18-12, 03:41 PM   #4  
Have you cleaned/changed the air filter? Had to borrow a neighbors mower back in VA when mine was being repaired...similar symptoms. Changed the filter..all was good.

Air filter should be changed every year.


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07-18-12, 04:13 PM   #5  
Post some model numbers for the mower and the engine so we know what you have, you are asking how long is a rope. Have a good one. Geo

 
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07-18-12, 04:21 PM   #6  
Agreed.. is this a big zero turn mower, a regular riding mower, a push mower, what engine, etc...???


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07-19-12, 04:08 PM   #7  
This is a simple and small push mower by MTD Briggs & stratton, 500 serious, 11A-084E029, <4Hp (?). I have replaced spark, spray carborator cleaner from air intake by removing filter and clean filter every one or two cuts, but did not change filter yet. Since 1st day I bought the mower ~1.5 years ago, the filter was filled with some oil ( not gasoline) and was not as dry as my previous one, which was Murry 20" and went to same situation.
When I stop pushing mower, the engine does not come back to full speed.

 
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07-19-12, 07:04 PM   #8  
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. Check the intake tube to see if the O ring seal and plastic retainer are still on the intake tube, if so remove them and re-install them into the carb. 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), now with a small screwdriver pry out the main jet(carefully) and clean it, check the O ring on the main jet for damage, if it is damaged it must be replaced, 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(not necessary if the fuel tank was clean). 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

 
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07-20-12, 09:35 AM   #9  
How difficult is it? The filter with oil and not dry is normal?

 
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07-20-12, 09:49 AM   #10  
The filter should have a light coating of oil. You soak it with oil and wring it out. It it's heavy with oil, wring it out.


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07-20-12, 07:34 PM   #11  
Follow the instructions step by step and you will have no problems. Have a good one. Geo

 
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07-23-12, 06:27 AM   #12  
last weekend I bought the kit and was going to follow your instruction to do something. Before do anything, I tried to start mower and wanted to run off gasoline. But, this time, I can not star mower anymore althoung gasoline is full. Under this situation, should I continue to do or is there any other things happened? Please advise.

Thanks

 
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07-23-12, 06:44 AM   #13  
It is possible something else happened. First I would proceed with the carburetor repair and see if that fixes the problem.

You can drain the fuel from the tank or use a pair of vice grip pliers, "C" clamp or something similar to pinch the fuel line closed before disconnecting it from the carburetor. Then tie a piece of string or wire around the fuel line to hold the end of it above the top of the fuel tank to prevent fuel from leaking out.

 
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07-23-12, 09:31 AM   #14  
Pilot Dane;
That model doesn't have a fuel line, carb sets on top of the fuel tank. Have a good one. Geo

 
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07-23-12, 09:34 AM   #15  
Even better. No worries about fuel leaking out when you remove the carb.

 
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07-23-12, 10:34 AM   #16  
how to check if carburetor has the problem? In addition to #5803 kit, is there other part I should have? Because I have two mower with same problem, I am going to repair before buy new one. Please let me know what kind is the defect should look like. Is it worth to send for repairing, if i can't find?

 
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07-23-12, 12:53 PM   #17  
You are trying to make a simple fix difficult, you will see nothing wrong when you remove the old parts, they aren't broken just lost the flexibility necessary to pump fuel. After you remove the carb and tank pour the fuel in a clear jar so you can check for water in the fuel, also use fresh fuel, fresh from the pump not fresh from a can that has set since last year. Have a good one. Geo

 
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07-25-12, 06:01 AM   #18  
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I have put the pictures about the mower. Please advise where are the two bolts, 3/8" and 1/2", I should remove to slide carb/tank? " Slide Carb/tank" means the carb should be linked with tank? Where is throttle linkage? Is it linked with two springs (very loose)? Where is intake tube, rubber or AL? These may be my first step, I try to do mechanic job first time and need learn lots.

Thanks

 
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07-25-12, 06:11 AM   #19  
Take out bolt #1 and # 2 and slid gas tank and carburetor off as an assembly, remove linkage when tank and carb comes of intake tube, then you will see O-ring seal. Then remove 5 phillips head screws that hold the carburetor on gas tank, then the diaphragm and gasket will be exposed. Good luck!

 
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07-31-12, 06:16 AM   #20  
I have done what you suggest. It sounds good. Thanks

 
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07-31-12, 08:31 AM   #21  
Success is a wonderful sound. Have a good one. Geo

 
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