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4.5Q Briggs & Stratton carb removal questions

jagman's Avatar

Join Date: Jun 2005
Posts: 5

06-28-05, 09:07 AM   #1  
4.5Q Briggs & Stratton carb removal questions

Based on your comments in previous posts, I believe the problems I'm having with my 4.5Q are related to the carb diaphragm. The mower is barely 2 years old, it worked fine last year, I've had problems all summer this year, the idle is erratic, and it burns much more fuel. I've changed the air filter and it hasn't helped.

I tried to remove the carb. to replace the diaphragm but couldn't get the carb off. My model has the carb sitting on top of the fuel tank. The carb is held by 5 phillips screws. When I remove all 5 screws, the carb itself attempts to lift up but I can't separate it from the mower. The metal "arm" that controls speed is still attached to the white plastic "boomerang" shaped object on top of the carb. Also, the large plastic hose fitting between the carb and the engine is loose, but won't come free.

How can I safely remove the carb without breaking it? Do I need to disconnect the metal arm first? How can I separate the carb from the large plastic hose fitting behind it?

Also, an extra o-ring fell out when I was attempting to remove the carb. One 0-ring sits on top of the carb neck under the air filter. Where does this second (identical to the first) one sit?

Thanks for all your help,


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Azis's Avatar
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06-28-05, 09:35 AM   #2  
hey jagman,
Ur almost there hehehe, leave the carb connected to the tank, remove the bolts holding the tank on. One main bolt with a bushing and perhaps one or two on the front connecting the speed linkage bracket.
With the tank/carb assy loose from the engine, lean the assy to allow the z-bend on the end of the metal rod in the boomerang thing to come out...the hose can come off of the engine or carb or both, it is only stuck a bit just twist and tug persuasively not violently
Now you should be able to seperate the carb. Be sure to clean the pick up tubes and now is a good time to clean the tank as well.

jagman's Avatar

Join Date: Jun 2005
Posts: 5

06-28-05, 10:15 AM   #3  
Thanks a bunch. I'll have to try that when I get home.

cheese's Avatar
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Posts: 16,573

06-28-05, 10:53 PM   #4  
I think the oring you see is from the carb throat where it connects to the engine intake tube. The oring goes in, then a plastic ring goes in to lock it in place.

"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

jagman's Avatar

Join Date: Jun 2005
Posts: 5

06-29-05, 06:51 AM   #5  
Thanks to you both. I was able to follow your instructions yesterday and quickly removed the carb. I found that both the gasket and the diaphragm were damaged badly. I'm having a hard time locating the kit here in my hometown as it seems that the regular suppliers in town are out of them.

Thanks again for your help.

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