Outdoor Power Equipment and Small Engines - Maximum vacuum from mower deck

Given I have a toro recycler 21", what is the best engine speed for maximum vacuuming for lifting twigs and debris when mowing. I've heard 3050 rpm and heard about blade tip speed concerns, so what do you think?

Just allways have it at maximum velocity and you will do fine.

What is maximum velocity? I can alter the engine speed and see from other posts that most small engines run at 3600. Is that the best/max velocity?

Full Throttle. If you adjust it, don't adjust to much that you burn up the engine.

Term is right. The most RPM's will no doubt give the best vacuuming effect. The Consumer Products Safety Commission says that blade tip speed is not to exceed 19,000 feet per minute. What does that mean to you? If an authorized service shop were to service this machine, they would be obligated, by law, to set the engines' max. rpm's not to exceed about 3100 rpm on a mower with a 21" blade. This setting would be different on a mower with a 18" blade (more rpm's), as would it be for a mower with a 24" blade (less rpm's). If you do your own tuning, always be aware of the danger of increasing rpm's. A small engine can generally be safely run at 3600-3800 rpm's

Hello: mitchella.

Maximum vacuuming is not fully attainable with any recycle mower nor any multi-purpose (2 in 1 or 3 in 1) mower designed for residential usage. Nor at any engine speeds. Here is why.

Deck design.
&
Blade design.

Older mowers had flat decks. The blade was close to the top underside of the deck. The blades design was angled for max suctioning.

New multi purpose mowers and recycle mowers have donut shaped decks. They look like they where molded over a tires side wall. Domed slightly or highly domed.

The dome shape changes the air flow pattern so the clippings can be multi cut several times before some of them or all of them are deposited back onto the lawn.

A true recycler mower has no shoot to catch clippings. A multi purpose mower can do both recycling & catching some clippings or more. But not all clippings.

Therefore, if the mower you have is only a recycler only mower, it will not have any means to catch clippings. If that mower is a multi purpose machine, it will have a means to catch clippings.

Regardless of which type and style the machine is, all non commercial, residential only type mowers, have domed decks. Thus engine speed will not aid much in catching clippings.

To obtain max vacumm action, a commercial machine is required. Which are rather expensive. Mostly do to the fact they are built for commerical daily usage. But they also have slightly different deck designs. Look closely to notice the differences.

Commerical machines are designed to achieve max suctioning for a clean professional look after mowing. At the expense of not leaving clippings for refertilization and dumping into landfills, etc.

Thus, raising engine speed will not achieve much, if any additional suction power with any multi purpose mower and certainly not with a mower designed strictly for recycling only.

A change to a high lift blade will aid some but often not by much on any muti purpose machine and or recyler only machine. Which is why I will spend the extra $$$$ for a commerical machine...:)

So long as the environmental agency is involved in the process of reducing landfills, saving the environment, etc. multi purpose machines are here to stay for the residental user.

Recycling clippings does have it's benefits. Less clippings sent to the landfills and refertilizing the lawns. It also has it's drawbacks.

"My Two Cents."

Regards & Good Luck. Sharp Advice.
Master Small Engine Tech. Web Site Host, Forums Monitor and Multiple Topics Moderator. "Accurate Power Equipment Company." Small Engine Diagnostics Services & Repair.
Fast...Fair...Friendly & Highly Proficient Services....:D