Farmall 450 Won't Turn Off

FarmallLovinGuy · Mar 6, 2017

Have a Farmall 450, and sometimes it will not shut off. It usually has this problem after running it awhile, such as one the road or when the engine has a chance to heat up. When it won't shut off, exhaust comes out from under the air filter. Is it because of carbon deposits in the cylinders? Also, fine carbon particles occasionally come out of the muffler when I start the tractor, landing on the hood. Is there some kind of additive that I can add to the fuel to clean this up if the problem is carbon in the cylinders? Thanks

David G · Mar 6, 2017

Does it make loud noises when it does this?

old · Mar 6, 2017

If it is dieseling as in run on after shut off but not running as such then your likely to have the main jet set to rich and or hot spots in the engine. Put a quart of ATF in 2 gal of gas and run it that way. Also when your ready to shut it off idle it down as slow as you can and let it idle for a few minutes before you shut it down. Also it might be a good idea to service the air cleaner it could be full of mud and water which will also cause it to run rich

gene bender · Mar 6, 2017

Nothing new hi-dome pistons will do that just put it in gear let the clutch out and hit kill button. Mite be time for new plugs i would check them

John M · Mar 6, 2017

What plugs are you running?

Id just shut the fuel off and let it die.

charlieu · Mar 6, 2017

(quoted from post at 23:36:58 03/06/17) Have a Farmall 450, and sometimes it will not shut off. It usually has this problem after running it awhile, such as one the road or when the engine has a chance to heat up. When it won't shut off, exhaust comes out from under the air filter. Is it because of carbon deposits in the cylinders? Also, fine carbon particles occasionally come out of the muffler when I start the tractor, landing on the hood. Is there some kind of additive that I can add to the fuel to clean this up if the problem is carbon in the cylinders? Thanks

Dieseling is the reason that the 656, 706 & 806 gas engines had an electric solenoid on the carburetor. When the switch was shut off the needle went on the seat stopping the flow of gas into the engine.

Janicholson · Mar 6, 2017

To fix it the solutions are: make sure the idle speed is as low as you can make it run. 400 to 450 RPM is pretty good. Second make sure it is not running rich at Idle adjust for a 'leanish' idle, which is just not quite as happy toward lean (Idle circuit only. Third (as mentioned) put it in 5th TA forward, and as you shut off the key, let the clutch out to stop it. Jim

FarmallLovinGuy · Mar 7, 2017

So I should use automatic transmission fluid? Is that what ATF stands for? And mix 1 quart in 2 gallons? Does this help to clean the cylinders out? So I'll clean out the air cleaner and then run it with ATF and see if that helps. How would I know if it is set too rich, and how would I fix that? Is this what you mean by ATF (picture below).

FarmallLovinGuy · Mar 7, 2017

It makes some noises, but I wouldn't really say that they are loud. It just keeps going, and then will eventually shut off

jeffcat · Mar 7, 2017

You also want to check your timing. A degree or two will mess ya up. I would think by now someone would have said something about a can of sea foam in the gas. Good carbon cleaner!.

old · Mar 7, 2017

Yes ATF is automatic transmission fluid. ATF cleans out carbon deposits etc. As for running rich if you see any black smoke when it is running that says it is running to rich

littlefarmer · Mar 7, 2017

I have a Farmall M that I use for some heavy field work, and this "dieseling" is a frequent problem in these engines.

Solutions (in order they should be tried):

1) Letting it idle for a minute or two after a hard run can help.

2) I only run Premium gas in my M. That really helps, and the extra .10 - .15 cents a gallon is worth it. Modern unleaded fuels are way too low octane for these older high compression tractors. I think IH recommended 90 or 91 octane for these engines.

Letting the clutch out while in gear to stop the "dieseling" is kinda dangerous. The tractor can lurch ahead and hit or run-over something.

David G · Mar 7, 2017

Dieseling breaks things, so it needs to be stopped.

Idle speed to high, excessive heat, excessive carbon, excessive fuel are all contributors.

You might have to take care of all of these items.

used red MN · Mar 7, 2017

To add to what Jim N. has said. The idle air jet is number 2 if the photo loads. At idle turning this screw should make a huge change in the idle speed and quality. Try adjusting as Jim suggested so In and out until the idle is good then adjust out until the idle is bit uneven but not terribly unsteady. This will be a lean setting as you are adjusting air. Quite often there is something plugging the idle circuit in the carb so to compensate the idle stop 1 in the pic is turned in. This raises the idle speed to compensate for the dirty carb issue. Thus causing a greater run on or dieseling when trying to turn off the engine. You don't want to hear my recommendation for carbon removal, the faint of heart on hear would have me arrested for tractor abuse. Lol.

D beatty · Mar 7, 2017

You way of cleaning carbon wouldn't be getting engine hot and metering water through engine Which will snap carbon and then change oil ? You can also take it to the field and work the snot out of it for 3 or 4 hours.

John M · Mar 7, 2017

So kerosene is high octane??

jeffcat · Mar 7, 2017

NO.....

jeffcat · Mar 7, 2017

I agree John. I just love NGK Copper core plugs. Have solved so many crazy problems with my stuff. He might want to make sure he has WIRE wires!!! Carbon type can cause problems also. I also use HI -TEST in everything. He might want to go to the local aitrport and buy a few gallons of 100 or 104 Av gas. Wow wow wow do things ever run better with that stuff. You need to totally readjust the carb to work with it but well worth it. Not kidding about the AV GAS!

Russ from MN · Mar 7, 2017

High compression? What has been done to it? They were very low compression when new.

John M · Mar 8, 2017

I know. My point was when the tractor was built, in this post reply, a Farmall M, they started on gas and ran on kerosene/distillate. To say "high compression" and "high octane" when refering to an M makes me chuckle. GRanted, there were high compression "kits" both factory and farmer-installed, but lower octane gas wasn't a problem, most of the time. (OH GOD, WHY OH WHY DID I SAY THAT!?)

caterpillar guy · Mar 11, 2017

Timing ,points,and plug gap will all affect that. Worked for a guy with chevy trucks for hauling grain if the one would go to dieseling he would adjust the points to solve it. I thought he should have just put a tongue in the front and got the tractor out and solved the whole chevy thing.

kcm.MN · Mar 11, 2017

Going back to the OP, he wasn't real clear about whether the tractor dieseled or if it simply would not shut off, as though you hadn't tried. If you turn the key and notice no change, then check the ignition switch. Check first for a loose wire as this can happen.

But more likely I would say he was speaking of dieseling.

Farmall 450 Won't Turn Off

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