Carburetor adjustment or if unattainable rebuild the carb. about $20 and 1/2 hr
Before you start messing with the carburetor, check the air and fuel filters.
Top no-load speed is 3050 rpm.
Depends on gearing and weight, but they will run around 3600 rpm, if that helps you.
Depending on the model, 3600 - 4000 rpm top no load speed.
go to B&S site, they have all your settings and info that you need. 3600 rpm is the norm.
on the carb there is a plate that moves when you throttle up and returns to a stop screw when throttled down. This stop screw is the idle adjustment, turn it in until you reach your desired idle rpm.
All Briggs engines run at 3000 rpm. Slacking off the 10mm nut on the gov lever adjusted the arm of the gov to which ever speed you whant but be careful not to over do it
You need to either adjust your carburetor richer or leaner while at full throttle.
It is generally caused by improper valve adjustment. But can be caused by excessive RPM. On the 17.5 the intake push rod is most often the one bent or broke. Try idling down the engine prior to turning it off.
7100rpm
It could be that the mixture is a little on the rich side. Close (rotate clockwise) the needle valve on the carburetor about 1/8 of a turn.
it could be caused by a few different things. the pneumatic governor or a fuel issue. an easy test is to hold the throttle on the carb closed to an idle. if it continues to surge then it is a carb issue, if it stops it is a governor issue
I guess I could have explained more thoroughly I have changed the air filter and fuel filter and changed spark plugs and also disconnected the kill swithes on mower to make sure that was not it either plus I changed the oil too