Lawnmower won't stay running

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  #1  
Old 03-15-07, 01:07 PM
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Question Lawnmower won't stay running

Hello,

The other day, I was given a non-working but complete Murray mower with a bagger and a 4.5 hp Briggs & Straton engine. The starter cord pulls the way it's supposed to. The throttle cable binds a bit, but this is easy to work around. The mower's eight or nine years old, and worked well until last summer when it wouldn't start one day.

I put a new spark plug in, and it's getting spark. I took the nut off the bottom of the float bowl, and gas started flowing out, so gas is getting to the carb. I removed the carb and cleaned everything with carb cleaner and Deep Creep. Then, I put everything back together and shot some starting fluid into the intake. It ran for about two seconds and stalled. I disabled the safety interlock and tried again. This time, as long as I sprayed carb cleaner into the intake, the mower would run. Once I quit, it stalled.

Now, the nut that holds the floatbowl on was labeled D and had a couple of holes near its bottom. It looks like a jet of some kind. I carefully cleaned it when I had everything apart. Does that nut need to be lined up a special way for the machine to work? Also, it doesn't sound like the primer bulb is pulling any fuel into the carb.

Could this be a problem with that jet nut or a bad float bowl? Any suggestions would be appreciated.

Thank you,
-Bill
 
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  #2  
Old 03-15-07, 02:04 PM
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You should check the float first. A hole may have rusted through and let gas in. Shake it and see if you here any gas.
 
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Old 03-15-07, 02:15 PM
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Originally Posted by msidan View Post
You should check the float first. A hole may have rusted through and let gas in. Shake it and see if you here any gas.
The float's plastic, does that make a difference?
 
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Old 03-15-07, 02:43 PM
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Something else I forgot to mention is that this is a Murray pushmower 20" with a Briggs & Stratton Quantum XTE 4.5 hp engine.

Thank you,
-Bill
 
  #5  
Old 03-15-07, 06:34 PM
Azis
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Make sure the main jet, or bolt that holds the bowl on is clean clear through. There may be holes in the shoulder and one in the shank end, you should be able to blow through it.
If the primer bulb is working (not collapsed) but does not squirt fuel enough to start for a few seconds, it may be the bowl gasket leaking. It could also be the primer bulb itself. If it is hard to push and slow to expand, you may need to clean the body of the carb better.
 
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Old 03-22-07, 12:08 PM
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Any update for us WTK? By the way, the bowl nut (main jet) does not have to be in any particular position and if you have no primer action AND this has the primer bulb integral to the air cleaner housing (as opposed to integral to the carburetor) then you may simply need a new air cleaner gasket, which also takes care of the primer circuit. If the gasket looks OK then you may have a warped air cleaner housing body - at the point it mounts to the carburetor - and thereby not providing a good seal for the primer circuit. If you still have trouble, post back with such trouble, if any different, as well as the engine model, type and code numbers.
 
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Old 03-22-07, 02:56 PM
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Originally Posted by puey61 View Post
Any update for us WTK? By the way, the bowl nut (main jet) does not have to be in any particular position and if you have no primer action AND this has the primer bulb integral to the air cleaner housing (as opposed to integral to the carburetor) then you may simply need a new air cleaner gasket, which also takes care of the primer circuit. If the gasket looks OK then you may have a warped air cleaner housing body - at the point it mounts to the carburetor - and thereby not providing a good seal for the primer circuit. If you still have trouble, post back with such trouble, if any different, as well as the engine model, type and code numbers.
Funny you should ask. I was working on it today. Part of what I did was to replace the primer bulb, but in doing so, I punched a hole in the new one. So, I'll be doing that again.

After priming it, it would start and run for a couple of seconds, then quit. I checked the bolt that holds the bowl and it's clear. I can blow through it now.

It looks like the gasket between the air cleaner housing and the carb is bad. They stock alot of B&S parts at the nearby Ace Hardware, but the gasket and other more involved parts, like carb innards, are nowhere to be found. Where does that sort of thing come from?

Looks like I'm on the right track, but not quite done yet.

Thank you,
-Bill
 
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