Hot-Rodding a Sawmill Motor

You can increase the RPMs (and horsepower) of small engines with minor control adjustments, but that doesn't boost the important factor: torque. July 28, 2006

I have a small engine question. I am in the middle of building my own bandmill. I have a 16 hp Briggs Vanguard. I read a lot of comments about the great improvement people see when going from 15/16 hp to 20+ hp. When you compare a 16 hp Briggs to an 18 hp, the only visible difference is the sticker that indicates just that. I had a small engine guy tell me that the only difference is the size of the jet in the carb. If this is true, is it not conceivable that my 16 hp Briggs could easily be converted to an 18 hp by changing that jet? If so, I would love to do it, but maybe it's not that simple.

Forum Responses
(Sawing and Drying Forum)
From contributor B:
It may be easier than that! Some Briggs engines have a throttle stop to keep the carburetor from opening all the way. Check your throttle linkage at the carb for a roll pin that stops the throttle. Smaller engines also have a D shaped intake runner that chokes the air/fuel flow to lower the HP rating.

From the original questioner:
Thanks for the response. The same guy that told me about the jet in the carb also told me something similar about the carb linkage. I have a tachometer on the engine and am able to run it at 3500+ rpm. I realize more rpm will produce more hp. However, I wonder if running at 3600 or more is bad for the engine. Where is the true, safe redline? Or, do I have it wrong? Will the governor maintain the rpm while the modified carb linkage applies more fuel and therefore more oomph to the top end performance? I know small engine guys everywhere are probably shaking their heads. But my lack of small engine knowledge is genuine.

From contributor B:
Most engines that size are governed at 3600RPM. Running it faster may get you more HP, but not torque. The highest torque is probably around 2200-2500 RPM. Torque is what keeps the saw blade cutting, not HP.