Zero turn engine speeds

[spasm3]

I happened to check my toro's full throttle rpm.
The mower is a 2012 I think.
The full throttle rpm with the blades off was 3240.

The Kawasaki site lists the full rpm( for an FR651V) as 3600.

I'm guessing this spring has stretched over time, as adjusting the throttle stop did not net more rpm. I shortened the spring a bit and adjusted the max speed to 3580 blades off. With the blades on it's now about 3480.

Big difference in cutting. I would get occasional clumps from grass building up on the deck chute and falling off. None of that now, and grass seems better mulched.

 

[AandPDan]

The Kawasaki manual, is that just the engine manual?
The reason it may not have been running at full rpm is the tip speed of the blade. It's best to see what Toro set it for.
OSHA limits tip speed to 19000

 

[football]

What he said. The govt limits blade tip speed on the lawn mower blades. They factor in pully sizes, plus engine RPM, to get the correct blade speed.

3600 RPM is probably way over the limit.

Yes, bumping up blade speed to over the govt limit has always increased mower performance.

 

[spasm3]

The Kawasaki manual, is that just the engine manual?
The reason it may not have been running at full rpm is the tip speed of the blade. It's best to see what Toro set it for.
OSHA limits tip speed to 19000

What he said. The govt limits blade tip speed on the lawn mower blades. They factor in pully sizes, plus engine RPM, to get the correct blade speed.

3600 RPM is probably way over the limit.

Yes, bumping up blade speed to over the govt limit has always increased mower performance.

I think you are right. I found the manual online for the mower blade speed, 18.330 @ 3400.

I'm going to leave it, as its 3580 rpm pto off. with the blades on, not moving its 3480 rpm. I don't know how much blade speed increases with engine speed. but i'm probably a bit under 3400 under load.

I still think it was too slow before. 3240 with the blades off.

Thanks for the insight.