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I have a Toro Timecutter 75734 with a Kohler KT725-3097. It is a few years old with about 140 hours on it. My question is about doing a valve adjustment.

How do I know that I need one? Is it difficult to do on this engine? Any danger in not doing it or pushing it off?

The mower runs great although it was sputtering 1-2 seconds sounding like it was trying to start back up after I turn the key to kill it. I cleaned the prefilter on the airfilter (it was filthy) and this seems to have remedied this shutdown behavior.

Hello S,

It is not a matter of waiting until you hear any noise or experience a breakdown. The valve adjustment is to keep the engine running efficiently and avoiding major damage due to a push rod jumping and getting pinned at the edge of the rocker saddle which bends them.

I usually recommend a valve adjustment check every 250 hours as preventative maintenance. (Kohler recommends every 500 hours, but that is stretching it.)

Parts wear inside of a running engine regardless of whatever kind of oil is being used, so don't prolong your oil changes.

There are some very good professional small engine people on You Tube who can show you the procedure. Avoid the ignorant DIY "goobers" who talk to the camera the entire time. Donny Boy small engine and Teryl Fixes All are pretty good. Teryl likes to make ignorant skits and wear fake teeth & hair, but he knows his stuff with all kinds of small engine equipment.

EDIT:

In this fast-paced (busy) world people tend to always be in a hurry to jump on a mower, then wind up the engine and drive like a NASCAR driver to get the grass cut. When they are done, they rush to shut down the mower engine and move on to the next task on their schedule.

As for the engine still trying to run for a second after cutting the key off, I suggest you make sure the engine is at a low idle for about 30 seconds to slow down the engine momentum, then turn the key off. If you shut down at high RPM, the engine is very hot and will try to keep running due to high cylinder temperatures that will still combust the fuel being drawn in, even with the ignition turned off.

Some diehard purists would say it needs an "after run solenoid". Those solenoids are nice when (and if) they work, but they get sticky due to the fuel. Practically all fuel ages quickly and has refined additives in it that gum up, or people use a "snake oil" fuel stabilizer (pick your favorite flavor).

I have found (from many years of small engine experience) that installing a simple shutoff valve in the fuel supply line is much more reliable. All a person has to do is idle the engine down, then shut off the fuel valve to let the engine wind down to shut off.

The important thing is to remember to cut the key off to prevent the battery from draining down.

By using a fuel shut off valve, it also helps remind people to slow down for a second and check their oil level before turning the fuel on and firing the machine up to put it to work. Lots of small engines have been ruined due to low oil volume.

At least it is accessible after the engine guard (tail fender) is removed not like the Hustler Super Z currently in the shop here. To even remove the air filter cover you must remove the tail fin and to adjust the valve the engine has to be unmounted.

Or like some Gravely mowers where that engine has to be unbolted with all attachments just to replace the remote starter solenoid.

Or to access under the engine shroud on a Cub Cadet shaft drive where again the engine has to removed. On that one the insisted it only took 30 minutes. Kept insisting so I told him to prove it and I provide the tools and stop watch. He paid the bill and is barred from my shop.

And some wonder why we charge so much to do certain simple sounding jobs.

Check the valves yearly for a good runner. Only takes about 3 minutes. I don't use RTV that's why so fast. RTV used you will be out there all day.

slomo said:

Check the valves yearly for a good runner. Only takes about 3 minutes. I don't use RTV that's why so fast. RTV used you will be out there all day.

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How do you do it without RTV?

slomo said:

Check the valves yearly for a good runner. Only takes about 3 minutes. I don't use RTV that's why so fast. RTV used you will be out there all day.

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Nothing only takes 3 minutes, except checking the oil. If there is messy RTV all over the valve cover and cylinder head, it takes a while to correctly remove it. I use a wire wheel to speed up the process. Then if you use Permatex Right Stuff to seal it, that takes 90 minutes to set up before running the engine.

StarTech said:

At least it is accessible after the engine guard (tail fender) is removed not like the Hustler Super Z currently in the shop here. To even remove the air filter cover you must remove the tail fin and to adjust the valve the engine has to be unmounted.

Or like some Gravely mowers where that engine has to be unbolted with all attachments just to replace the remote starter solenoid.

Or to access under the engine shroud on a Cub Cadet shaft drive where again the engine has to removed. On that one the insisted it only took 30 minutes. Kept insisting so I told him to prove it and I provide the tools and stop watch. He paid the bill and is barred from my shop.

And some wonder why we charge so much to do certain simple sounding jobs.

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Hi StarTech,

I despise people who want to tell me how "easy" a job is when it comes time to pay the bill. The worst ones come in proclaiming that they watched a "professional" on You Tube and it only took "10 minutes".

What they fail to realize is that the video took over 4-hours to make when factoring in editing and filming segment retakes.... That's what they don't show, because no one would watch their videos if they knew the actual truth.

If I wrote repair estimates based on watching videos, I would be out of business very quickly.

It's never easy when you have to pull the entire rear end off of a mower.

shurguywutt said:

How do you do it without RTV?

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You can actually buy valve cover gaskets for that engine. You can also buy the upgrade composite valve covers with o-ring style gaskets.

I apply gasket sealer to a clean valve cover flange, next apply the gasket, pin it down to a flat surface overnight, next day when installing the valve cover the next day, only use grease or petroleum jelly on the engine side of the valve cover gasket. When checking the valves in the future, this allows you to gently remove the cover with less likely hood of damage to the gasket.
Thanks,
Douglas Lee
*

For the customers you don't like use permatex avaition sealant or indian head gasket shellac on both sides of a gasket.
Just say'in

Hammermechanicman said:

For the customers you don't like use permatex avaition sealant or indian head gasket shellac on both sides of a gasket.
Just say'in

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Hi Hammer,

Do that if you plan to never have them for a customer again because they have a "buddy" that can do the work "much cheaper". LOL

shurguywutt said:

How do you do it without RTV?

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Trick is a non hardening sealant. This stuff is great if YOU are the guy removing the cover next time.

For valve covers and oil pans. Use in aviation and automotive apps.