I have a Rally walk-behind rotary mower. It has a Briggs & Stratton 3.5 "Classic" engine with the "Chokematic" carburator. The engine runs very rich (almost stalling). I replaced the foam air filter, and cleaned the gunk off of the throttle springs and tried to make sure the throttle cable was not pushing too far into the choke/start mode... no luck so far...and it seems that this carb doesn't have any setting screws to adjust.

Questions:

--are there any adjustments on this carb?

--is there a fuel filter that needs to be changed?

--I'm wondering if the entire carb can be switched to the older kind with adjustments.

Briggs & Stratton's site was no help.

Thanks-in-advance for any advice

"choking on exhaust"
Connecticut

choking, October 2004

to choking of Connecticut. I'm maladjusted of Melbourne and have the same problem but i call it surging. Sorry to raise your hopes but I have no idea either. I saw Peter's response about the diaphragm . Please let me know if it's right.

alec, November 2005

you need to renew the diaphragm between the carb and the tank.It will be distorted which will cause the engine to run far too rich, also can cause it to run too lean.

peter, January 2005