Need help troubleshooting Briggs plastic carb

Ocean909

Active Member
Joined
Aug 11, 2022
Threads
8
Messages
76
Need some help troubleshooting a briggs plastic carb model 799584
mower model 09P702-0145-F1
Mower runs erratically and will die under load and can't be restated unless the carb is pulled and cleaned. Runs and dies with carb spray.
I've had the carb apart multiple times and can't figure out what I'm missing.


I've inspected the needle and seat
removed and cleaned the main jet assembly/ emulsion tube
sprayed carb cleaner through all passages and thet seem clear;
pulled and cleaned the choke butterfly and throttle plate.
Blew through the fuel inlet inverted and upright to make sure float and needle are operating correctly.
The carb seems spotless.

The only thing I haven't cleaned was under the welsh plug as I don't have a replacement.

Is there anything I've overlooked?

All help is greatly appreciated
 

Bertrrr

Well-Known Member
Joined
Mar 11, 2021
Threads
5
Messages
568
Might look at the fuel line - Can't think of anything else you might have over looked, " filter ?" Tank vent ?
 

ILENGINE

Lawn Royalty
Joined
May 6, 2010
Threads
43
Messages
10,732
The OHV push mower engine are fuel picky, I would try draining the fuel, and putting in fresh fuel that is recently purchased. I have seen mowers from customer that claim they are using fresh fuel and I can't even light the stuff with a lighter. Just because the fuel works in everything else you own doesn't guarantee that it will even start in the Briggs engines.
 

Ocean909

Active Member
Joined
Aug 11, 2022
Threads
8
Messages
76
Thanks for the replies.

Unfortunately its not the fuel or the line or tank. I swapped the carb out with another from a similar mower model and it runs perfect. Its something going on with this particular carb and I have no Idea what it could be.

I've had it off at least 6x and the results are the same. The mower runs like crap, I pull the carb, disassemble , clean reinstall and the thing runs for about 10 min then dies. rinse repeat. I hate trashing this OEM carb but I really am at a loss.
 

ILENGINE

Lawn Royalty
Joined
May 6, 2010
Threads
43
Messages
10,732
Sounds like something floating around inside of the jet assembly item 117 on this diagram

 

Ocean909

Active Member
Joined
Aug 11, 2022
Threads
8
Messages
76
When I don't feel like smashing it with a hammer I'll swap the carb's jet assembly with the working one and see what happens. Thanks
 

Bertrrr

Well-Known Member
Joined
Mar 11, 2021
Threads
5
Messages
568
Small gas engines can test your patience for sure
 
Top