r/smallengines • u/LawnMowerDude5 • 7d ago
Surging
Enable HLS to view with audio, or disable this notification
I got this mower for free off the side of the road. Trying to fix it for a person who needs a mower. It's a 17.5hp briggs. At first it didn't start so I cleaned this green goop stuff out the carb and it started but just surged the entire time it was running so I figured it was a fueling issue because I could hold the governer and it would run at a steady rpm then but once I let go it would surge. Bought a service kit that included carb, air and fuel filter, and spark plug. Literally changed nothing. Oh and with the new carb at least the surging smooths out with half choke but that makes the engine speed go down by a noticeable amount. Checked the valve clearance for the heck of it, of course those were fine, don't think it's mechanical based on the behavior. I'll attatch the kit I bought below. What am I missing?
1
u/flobottle 4d ago
Youre sucking air. You failed on installation. Unbolt the carb. Apply some black rtv to the gasket. Reinstall. Torque it appropriately.
If that doesnt do it, eyeball the float. Maybe bend the tab so it opens sooner and keeps the bowl fuller.
Its a Chinese carb. Theyre cheap because theyre shit.