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I have a Murray with a 450 series engine and I need a few more rpm out of it.

Before I remove the air filter is it able to be adjusted and if so how do I accomplish this?

Thank you!!

Chuck

Push mower max safe rpm's is based on blade length. the longer the blade the slower the engine is allowed to turn. What are the rpm's set at now. 19,000 foot/minute is the maximum safe blade tip speed set by safety standards.

I'm sorry I don't know what the speed is.

Thanks. I will have to make do with what it's set at.

Chuck

Calculate the circumference that the blade tips cover in feet the mulitply that by the rpms
So a 20" mower has a circumference of 5.25 feet x 3000 rpm = 15,750 ft/min
Or if you divide the max speed by the circumference you get the max allowble speed
19,000 / 5.25 = 3620 rpm max speed.
As there will always be some over reving on governed you would set that engine to 3400 rpm allowing +/- 200 rpm.