Murray push mower runs really low rpms.

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solefate

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09P702-0004-F1

I have a murray push mower that will start up first pull or two, but runs real slow, and the exhaust makes a popping noise each stroke. If I push on the throttle, or push in the primer, it will die. Also, when I take off the air filter, the rpms pick up just the smallest amount. The spark plug appears to be fine, though once it came out oily. I have cleaned the carb. Magneto is nice and smooth and I gapped the coil. Shaft is not bent. Any ideas?
 
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mechanic mark

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https://www.briggsandstratton.com/n...nginemanuals.html?searchrequested=09p702-0004

First check engine oil level, is dipstick showing overfull? If so, do you smell gas on dipstick? If so carburetor problem. Your carburetor part number is 590556. After locating your 8 digit code number, you may choose to locate & use overhaul kit for carburetor, kit # 590556.
https://www.google.com/search?sourc...q=b&s part 590556&aqs=chrome..69i57.15772j0j8

Check spark plug, air filter, engine oil & blade for replacement. Adjust valves with engine cold 0.004-0.008 per manual specs.
 
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solefate

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mechanic mark said:
https://www.briggsandstratton.com/n...nginemanuals.html?searchrequested=09p702-0004

First check engine oil level, is dipstick showing overfull? If so, do you smell gas on dipstick? If so carburetor problem. Your carburetor part number is 590556. After locating your 8 digit code number, you may choose to locate & use overhaul kit for carburetor, kit # 590556.
https://www.google.com/search?sourc...q=b&s part 590556&aqs=chrome..69i57.15772j0j8

Check spark plug, air filter, engine oil & blade for replacement. Adjust valves with engine cold 0.004-0.008 per manual specs.
Click to expand...

Yes it was overfilled, and I thought it looked too thin. Everything smelled like gas at this point so I can't be certain but probably is right. I will adjust the valves, and I ordered a carb kit. Will post back if it doesn't work. Thanks!




In case anyone wants to hear it - Running like poop
Can't see it too well but it also spits out a bit of fuel.
 
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solefate

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solefate said:
Yes it was overfilled, and I thought it looked too thin. Everything smelled like gas at this point so I can't be certain but probably is right. I will adjust the valves, and I ordered a carb kit. Will post back if it doesn't work. Thanks!




In case anyone wants to hear it - Running like poop
Can't see it too well but it also spits out a bit of fuel.
Click to expand...

Well, I ordered the overhaul kit and assembled it. All of the old gaskets were in like new condition, but I replaced them all anyway. Adjusted the valves, and I can tell the engine turns much smoother, though no higher on the rpms. Mower still dies when throttled, still runs better without air filter, and the spark plug always comes out black. Also, compression tested at 125.
 
BlazNT

BlazNT

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Clean that carb.
Dirty carb
Down and dirty: youtube.com/watch?v=VBL-BUj0c6E
More technical: youtube.com/watch?v=nAk_WDt3AD8
 
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solefate

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BlazNT said:
Clean that carb.
Dirty carb
Down and dirty: youtube.com/watch?v=VBL-BUj0c6E
More technical: youtube.com/watch?v=nAk_WDt3AD8
Click to expand...

I'll clean it one mo gain. Admittedly, I did not replace the seat in this thing because I was afraid of screwing it up. The carbs are like half the price of the mower if I mess that part up =P
 
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solefate

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solefate said:
I'll clean it one mo gain. Admittedly, I did not replace the seat in this thing because I was afraid of screwing it up. The carbs are like half the price of the mower if I mess that part up =P
Click to expand...

I have got to be missing something. I have sprayed this thing to no end, let is sit in chem dip, and shot it with air. Still the same. I adjusted the valves to 004, should I get closer to the end of the range? Also, when I brought up the parts list, it had a different numbered spark plug. Could it make that much of a difference?
 
primerbulb120

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Are all your governor springs present and in good working condition?
 
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solefate

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primerbulb120 said:
Are all your governor springs present and in good working condition?
Click to expand...

I only know of one spring. Also, when I move the throttle manually up and down fast enough for a minute or so, eventually the mower will take and rev up like it's supposed to for a few seconds. I assume its finally getting the right mixture at that point or something.
 
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bertsmobile1

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Replace the spark plug.
A fouled plug will miss and so just get more fouled.
 
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