I am working on a Briggs twin cylinder Model 407577, Type 0283-E1, Code 030821YG, that powers a lawn tractor. After pulling the throttle to slow and disengaging pto, the rpms remain high. Is there anything that can cause this other than faulty governor setting? Throttle linkage is fine.

Make sure the throttle cable hasn't slipped in the hold down clamp, Clean the throttle control assembly and cable. You may check the governed idle spring (pictured below) and the governor adjustment.


http://i107.photobucket.com/albums/m314/Restrorob/Briggs/Intek%20Twin/BriggsIntekTwinGovAdjust.jpg


Good Luck

Thanks Restrorob. Throttle cable is working fine. Will check governor settings after carb kit arrives and I replace it.

I had the same issue when I was working on a 25hp briggs powering a Husqvarna mower. Only after removing and reinstalling the carb(many times)with new gaskets did the problem finally disappear. Seems like it was sucking air in. It would idle back fine with the PTO engaged but would stay at higher RPMS with the PTO off. I had sprayed carb cleaner all around the mating services but never did find a leak that way. I'm sure the real techs will offer more advice but hope this helps some.

Guess I'm with Jack on this. Air leak somewhere. Loose bolts or gasket/oring leak at engine to intake, carb to intake, or carb to air cleaner. On big engines, the packing around the throttle plate shaft can leak.