Hello to all,

I'm new to the forum and trying to fix a DR brush mower w/13hp Briggs engine. I can start it and it will run at higher rpms but will not idle without surging continually. It appears that the Walbro carb is really rich! It will also kinda backfire out of the carb spewing fuel. When I engage mower blade, the engine will die no matter what the rpm's are. I've had the carb off twice, it's quite clean, has plastic float that is not adjustable. The idle screw has a plastic cap limiting much movement. Can't seem to figure this out...any suggestions out there? Thanks. :cry:

Sounds like your valves need adjusting, whats your model, type and code off your engine?

mod.#21A977
type.#0119E1
code.#020322zA

Check your valve lash, 145psi of compression is a bit high, rotate the engine 1/4 past Top dead center and measure valve lash with the front valve cover off. Intake and Exhaust should be between .004-.006".

Ok, I'll check the valve lash and see what it tells me. Probably won't be able to post about it till tomorrow evening though cause I'll be out of town. Thanks a lot for the info!