I cleaned the carburetor and replaced the carb gaskets, and replaced the spring underneath the governor air vane. After putting it back together I adjusted the rich/lean screw and turned the collar under the air vane clockwise to bump up the RPM. The mower is cutting fine and I get good response from the self-propelled. I do not have a tach, and I suspect that I do not have the RPM cranked up as high as supposed to be. But since I don't have a tach I am worried that if I get them too high it will be bad for the engine, correct? Is there any harm to the mower in running it with the RPM set below spec?
#2
Teds
You can buy digital tach, inductive type for small engines - for eight bucks, delivered. Check that auction site.
Don't know about harm to the engine, but the quality of the cut may suffer. LawnBoy mowers excelled in this for a few different reasons, one of them being high RPM, or maybe a better way to put it, they don't bog down, the governor is quick and responsive. Federal regulations limit a 21" blade to 3200 RPM or somesuch, consequently you want every bit of that. They were designed and engineered for 3600 RPM. Add to that a quality sharp, balanced, and straight blade, it will plow through even thick wet grass without complaint. I've tried quite a few different push mowers and there is really no comparison. The fact that they are so lightweight seals the deal.
The deck is designed for a specific engine speed usually +/- 100 rpm
Most will spin anywhere from 3200 rpm to 3800 rpm and are safe to a little over 4000.
The "deluxe" & "quiet" models spin a little slower and that makes a massive difference to the sound level both from the engine & the blades.
