OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Height Range for a SB 45

If the reel is touching the bedknife, it needs to be adjusted immediately. There are a couple of SB threads here that will tell you how to do that.

The Briggs and Stratton engine has a governor, so there is no throttle control that the operator handles. The control you have adjusts the engine's speed setting, then the governor adjusts the throttle to maintain that speed, regardless of load (unless you get to maximum throttle and that isn't enough to pull the load you've imposed on it). You will notice that when you turn the mower upward on a slope, you can hear the exhaust get louder without the engine speed changing.

You need to ensure that the speed control covers the full range of the governor lever that it connects to at the engine-end of the cable, on top of the carburetor. If it does not, you may not be getting full engine speed from the governor. There should be a little tin-pot clamp that holds the bottom end of the cable outer stationary. It is held to the cooling air cowl with an even more tin-pot self-tapper. Often the self-tapper self-transports itself out of the hole and onto the ground, leaving the cable outer loose, so it slides back and forth when you adjust the speed control. Check for this. If the clamp is missing, you need to get or make one - it's a sixpenny part. If the self-tapper has stripped the thread in the air cowl, just use a bigger self-tapper, and don't over-tighten it like the last guy did.