You should tach it to be sure before and after adjustment. RPM should not exceed 3400. Max. blade tip speed is 19,000 FPM. As far as how to adjust this particular one, I don't know, but you can manually 'goose' the governor lever at the back of the engine while it's running to temporarily speed it up. If you do this and observe the linkages you may see how to adjust it. I'll do this and run mine up to maybe 4000 every so often just so the connecting rod doesn't shrink. ;)

Some links use a threaded stop. The spring can be hooked in the lower hole of the arm (if applicable).You can also tweak the leg of the governor arm back. It is good advice to have someone with tach do it.

Thanks for the information. I was able to find the linkage that controlled the governor. When I started looking at the cable that controls the throttle, it showed that it had moved. I took it to a honda dealer and they were able to tighten the cable for me which made it run better.

Thanks again,

Mark

In most cases the engine should never be sped up past its factory engine setting described in the owner's manual.

If the engine on your mower is running at, for example, 3100 RPM, 5% overspeed would mean 3255 RPM while 10% overspeed would be 3410 RPM.

Optimal no-load speed settings to consider, so as to save wear and tear on the engine, in my mind, would be 2900 RPM for 21" mowers and 3200 RPM for 19" mowers. These suggestions are given in compensation for maximum available engine torque. My 1984 Toro 20672 with its Tecumseh-made TNT100 engine is currently set for 2900 RPM.

The smallest Honda mowers that used to be sold here, the HR17 and the HR173, had a 17" cut width; optimal engine RPM on those would be 3500.

Blade tip speed on your 21", if the engine runs at 2900, would be around 16,000 fpm.

~Ben