OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames 375 sprint idling

hi everyone
i'm working on a 375 sprint that had dirt in the fuel tank. i've cleaned that out and the carby,it still ran rough and cut out when it idled. i put one of my carbys on it and its ok except the govener spring had been stretched to the max at some time. i got a new springs,the big one was coded green, the small ones just silver. anyway it seems to run good,but the cut out stops it before i can get it to idle low enough.i have been bending the arm the spring hooks onto to adjust it.i either get it to idle good but wont rev up or else revs but no idle. it seems to be all to do with that spring but i can't seem to get the best of both full throttle and idle.the guy in the shop said it was the right spring so i dunno its got me a bit buggered cheers

You have two arms (lugs) that can be adjusted so I assume that you have been only bending the throttle (high speed) one and not the idle one.

First adjust the idle lug to get the correct idle speed and then adjust the other lug to get the correct high speed RPM'S.

Doesn't the 375 Sprint use the same idle speed as all the other small B&S engines - that is, 1750 RPM? B&S say that you mustn't run them slower than that because the cooling air flow won't be sufficient. That is why they design their governors to only operate at 1750 or higher speed (1750 RPM is no kind of idle - it's quite fast enough to mow the lawn if you've got 4 blades or walk fairly slowly).