B&S engine surges

trailwart · May 11, 2007

i have an old simplicity 4211 with a B&S 400cc i/c 11hp engine. my problem is after about 5 minutes of runnin the engine starts to run up and down in the rpm's. also where ever the throttle position is when i start is where it stays after its running, it will not adjust with the throttle lever. i believe i must have lost a piece of the carb linkage or a spring of some sorts. not sure what the cause is. any suggestions. thanks

escavader · May 11, 2007

When most briggs engines surge up and down,there is a Peice of crap behind the main jet,happens alot.start it,reach down under the carb wind the jet out til it starts to run real bad ,then wind it in til it runs bad,then put it back half way.If it was a peice of crap,or a gumed up jet it should be all better now,it passed it by.I do this occasionally after the briggs i got sat for a while,i also will go over to the neighbors and adjust his cause it drives me crazy heARing it surge up and down,Also sounds like your throttle cable came un hooked,take the breather off and see if the carb is opening and closing properly.
ALAN

trailwart · May 12, 2007

thanks for the help on this one. it was crab loaded in the carb bowl. half inch of rust in the bowl, took everything apart reassembled and runs great. thanks again

Bird · May 12, 2007

Glad you got it fixed. Another thing I've seen cause surging on Briggs & Stratton engines is a weak or missing spring for the governor.

Richard · May 12, 2007

trailwart said:
it was crab loaded in the carb bowl.

I always buy mine at the store, I wonder if yours was any more fresh?

trailwart · May 13, 2007

it wasnt a crab, i meant carp

escavader · May 14, 2007

Nice clean gas out of a plastic can,and a little stable to keep things from guming up over storage is certainly a little preventative helper.CRAP or sh..[ C R A P] ,i think carp is a fish aint it?

ALAN

trailwart · May 14, 2007

i shoot carp all the time with my bow,(lots of fun)originally meant crap, but others were funnin on that so i rolled with it. i need to get a new fuel gauge as mine is rusted on the shaft that the float rides on, i also put a new inline filter on. still have my throttle problem, if i start it with the throttle half up it stays or if its full up it stays. wont adjust with the lever after runnin, gonna go over the linkage again tomorrow, not sure whats goiin on.