I have a Craftsman with a 21hp Briggs. It just recently started to surge while in use and only smooths out when I have the choke a third out? Fuel pump going and needing a rebuild?
Check the intake manifold where it bolts to the carb. Mine is warped bad and it acts up including backfiring. When I smear some silicone on the joint it smooths out nice. Now I have a new manifold on order , it should be in next week.
using the choke increases the vacuum for the fuel. So my guess would be a clogged fuel filter or clogged carb. Have you run the engine out of fuel recently??
I have a Craftsman with a 21hp Briggs. It just recently started to surge while in use and only smooths out when I have the choke a third out? Fuel pump going and needing a rebuild?
Did this start (all of a sudden) or did you notice a difference in the way motor ran over a period of time - Did you get fuel from a different place then normal, by chance - Sounds like just a filter problem, When was last time it was replaced?
Have rebuilt the carb and fuel pump. Everything seemed fine. Replaced the fuel line from the filter to the carb, looked a bit worn. Replaced the fuel filter, seemed fine and clear. Problem came on sudden. Also does not seem to have quite the same rpm,s. Same prob with fuel cap off.
FOUND THE PROBLEM!!!!! "Even a blind Squirrel finds a nut once and awhile". Small Jet (pilot jet?) full of gunk. Should have done the soaking as suggested may have saved me the trouble. Thanks for the help and direction!
