Do You Throttle All The Way Down Before Turning Off The Engine?

[EricG1793]

I always idle down before turning the engine off if there is a throttle. If I've been mowing, idle a couple minutes before turning off.

On my 2004 Cub LT1018 with a Kohler Command and grandfather's 2007 Craftsman LT2000 with a B&S Intek, if I simply turn the engine off right after turning the blades off, they'll often backfire. I've never tried immediately turning off at full throttle after mowing, though. Likewise, starting the engine within a minute or two after it's been mowing often causes backfires.

 

[greggn]

I let the engine idle at a fast idle for a bit as well as a warmup at 1/3-1/2 throttle at first.

 

[1RB2534]

Got an email today on this thread, looks like it's an old ongoing one. Or at least probably every time an email reminder goes out on it.
I remember in the Army they told us we had to idle all our diesel equipment at least 5 mins before shutting off. But I surmise diesels get a bit hotter than gas engines.
In any case many of the briggs push mowers you buy now days don't even have a throttle. You prime the button and pull the rope while holding the idiot shut off safety lever against the handle. When it cranks it goes immediately to wide open. When you get done you let go of the idiot shut off and it immediately brakes to a dead stop. Done deal, it's kinda mandated by government, lawyers and or insurance companies. Same as the Ethanol they put in our gas that destroyed my chain saw fuel lines till I paid more for ethanol free fuel in the can at Walmart. After all that's what we pay taxes right?

So do I idle down, well yes when I'm not letting go of the idiot lever. I figure the engine feels a bit like me on a hot day and needs to walk it off after huffing and puffing. But then what does an old fart like me know anyhow.

 

[Tom S. in Tn.]

My old Tecumseh does not have a fuel shut off solenoid and keeps running and makes clattering noise unless the throttle is at dead idle.
Had a Briggs that would afterfire like a rifle shot after the engine shut off unless let run at idle for a couple minutes before shut down. If the crank did not stop turning after the key was turned off, it pulled fuel in and unburned into the muffler.

 

[whiteshu]

My John Deere 322 has a Janmar three cylinder engine. If I try to shut down at full throttle it will diesel. This could hurt the engine. So I idle down to the lowest rpm, an then shutoff. My John Deere X738 has a fuel injected Kawasaki engine. The manual instructs: Go to half throttle, then shut off.

 

[snesler]

Or, when you quit mowing, do you shut down the engine at full throttle and not concern yourself about it?

My old tractor style 46" deck, Craftsmen, powered by a 24 Hp, B & S Intek engine's manual never mentioned having to do this. So, I always left it going full blast when I killed the engine. I sold it to my next door neighbor with 350 hours on it and he is now running it with over 500 hours on it and he doesn't worry about shutting it down at idle.

My Toro manual says to idle all the way down, wait a minute and then turn off the engine.

What do you guys say?

Yes I do, you can ask any general aviation pilot the importance of proper warming and cooling of a piston air cooled engine and they will tell you to always slowly cool the engine and avoid what is called shock cooling, going from hot to cold too quickly. Full power is not applied until proper engine oil temperature is reached.
The next time you see a piston engine helicopter land, notice how long the the pilot remains in idle prior to engine shut down, usually one - two minutes allowing the engine to slowly cool.
An air cooled engine is an air cooled engine regardless of the application, warm and cool slowly is best practice.

 

[BlazNT]

Yes I do, you can ask any general aviation pilot the importance of proper warming and cooling of a piston air cooled engine and they will tell you to always slowly cool the engine and avoid what is called shock cooling, going from hot to cold too quickly. Full power is not applied until proper engine oil temperature is reached.
The next time you see a piston engine helicopter land, notice how long the the pilot remains in idle prior to engine shut down, usually one - two minutes allowing the engine to slowly cool.
An air cooled engine is an air cooled engine regardless of the application, warm and cool slowly is best practice.

Except for a lawnmower engine gets hotter when you lower the idle. The fan slows and the engine heats up.

 

[7394]

Its all those folks that kill engines at full throttle that engine re-manufacturers and for that matter, engine manufacturers love. Full throttle shut off does a few things to your engine. Allows a nice lean condition as the engine is slowing once the ignition is switched off as long as the anti-backfire solenoid is working. For those that either don't have a working solenoid or the solenoid has been disabled by the plunger shortened, there will be a full rich mode. Now, full rich does help cool the engine I'll give you that. Fuel that isn't burnt also cleans the lubricating facilities from the valve guide, cylinder, piston skirt and rings. The fuel that gets past the rings goes where?

We can go on and on from a machine shop perspective and thank you for continuing to shut down with WOT. lmbo. At any length, if the manufacturer is telling you to shut down WOT, then you bought from the wrong manufacturer. Brand loyalty used to come from longevity of products, ease of use, manufacturer truth, etc.

What has the world come to?

Max

Max- MY Toro Dealer told me to start & stop my Kawasaki engine at FULL throttle. :thumbdown: I showed him the manual I got for the engine from Kawasaki, & it states to start at idle & let warm up, then go to about 1/2 throttle before I engage blades, then wfo.
And shut down is stated to be idled down & then shut off. He called out the head mechanic & showed him what the book said. Head wrench said, I NEVER heard of that. (obviously, not a big reader)
Well I did. But I have also been doing it on all the mowers I had in the past as well.

 

[cpurvis]

I can't imagine any engine which would benefit from shutting down at full throttle, especially gas engines.

 

[upupandaway]

It says in the Stihl manual to idle for a min or 2 after hard work to cool down = (moving air and all) vs kill at high when everything is hotty hot.
Given this is from my 80's blower manual.

That's my 2,000Venezuelan Bolívar FWIW