For background I'm not a professional mechanic freely admitted but I like to tinker and learn. One of my bosses has this mower with a 725 Briggs that his brother gave him and he wanted me to see if I could get it going. It has set for quite awhile with gas left in it. Air filter was plugged. He had apparently let everybody and his brother borrow it. When I got it it would crank on ether but die when it burned the ether off. I replaced the carb. The automatic choke link had been twisted all up so I replaced it. New air filter and spark plug. Spark plug fires. At this point it would crank and run fine until it warmed up and then die. Choke not staying open so I tied it open. It still runs a little bit til hot then dies. I'm thinking coil so I replaced and gapped it. It still runs a little bit and dies. What next? Any and all help is appreciated. Thanks.
Briggs help please.
- Thread starter bovine1
- Start date
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- Dec 20, 2022
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- 327
How long does it run before dying?
I just watched a video about valve adjusting on Taradactyl youtube. He mentioned motors with too tight of valve lash running until the valvetrain heats up. Then the valve/valves stop seating. Hence compression goes away. In fact I'm due to maybe check the lash on my newer mower.
Motor cools, then it runs OK again. Not saying that is the issue. But it is easy to check lash anyway. MurkyAsparag us is asking the right question. In fact I might have stole his thunder..................
Motor cools, then it runs OK again. Not saying that is the issue. But it is easy to check lash anyway. MurkyAsparag us is asking the right question. In fact I might have stole his thunder..................
Issues with new carb ! sounds like float or needle and seat issue .
30 to 45 seconds is not long enough for a coil issue in my experience .
if its a flathead briggs almost certain its not a valve issue if its an ohv possible valve lash issue.
30 to 45 seconds is not long enough for a coil issue in my experience .
if its a flathead briggs almost certain its not a valve issue if its an ohv possible valve lash issue.
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did you remember to install the white plastic gasket ? before putting on the carb
You missed the part where he replaced the coil .
You can verify ignition by checking for spark loss when the engine dies. Still sounds like fuel. These carbs are so simple to take apart , clean and blow out. Everytime I service a carb. the tank comes off for a cleaning. A dirty tank will crud up a new carb. in short time.
Check the gas cap. I had a rider that would only run for a minute or so at a time, but would run with the gas cap loosened. The little vent hole at the top of the cap was all full of dust and crud. Blew some brake cleaner through it and boom, it would run again.
Auto choke, not auto chicken obviously...
The windvane on mine was binding up. I replaced everything and aligned everything and it has been great.
The autochoke has issues. It's not wanting to open. I changed the link but it's still not right. I warmed it up and tied it open and it still won't keep running. Valve adjustment nest. I'm trying to figure out a good way to rig the choke manual.
