Runs with switch off

I got a 1949 farmall m with mw pistons with a h4 mag which i timed so it clicks over just after the first mark of 2 marks and the tractor runs great but sometimes when you shut the switch off it will run over 2-4 times foward rarely does it go back words it has regular gas in it and compresson is 135 on all 4 cyl. dry check and just warm motor i was wondering if i should be runing premium.
Thanks Robertw

Slow your idle down.

Im lost, its not going to just stop all of a sudden when you push the switch in. They'll roll a little bit before stopping.

I have one with the same setup and have NEVER put premium in it. I have run E85, which is 105, but never "Premium" gas.

Slow the idle to just ticking over without stalling, as David indicates. 450 works if you can get there. If it will not stop dieseling, Put it in high gear, hold the brakes, and let out the clutch as it slows. I consider it very normal, and reducing the idle works well. Newer Farmalls were equipped with a fuel shutoff to prevent the problem. Cars (with carbs had either a fuel solenoid, or an idle stop solenoid to allow throttle closing. Jim

You have a hot piece of carbon in one or more of the cylinders. This is a very common problem. You can leave it in gear and let out the clutch part way to turn the wheels slightly to kill the engine, or lower the idle as others mentioned--if bad enough it will still run. I pull out the choke. It won't run without air. Some say that dumps gas in the cylinders and washes the oil off the sleeves -- maybe so. Your choice as to what you use. I don't like it firing like that particularly when it runs backwards so I picked the fastest way to stop it.

My Super M has done that for 30 years....Drop it into Hi gear before you shut it off,let out the clutch.

I didn't realize that it was that common just bought it a while back it doesn't do it all the time just once in a awhile.
Thanks Robertw

Just stop it in gear. They did that 50yrs ago with the Fire-Craters.

Shouldn't it trip at the second mark? if it is timed fast it may be building up some extra heat in cylinders.

No disrespect, but slow timing builds heat, you have it backwards.

like said,
slow down the idle,
and all tractors that have been working hard,
need a few minutes of 'cool down' time sitting there
idling before shutdown to prevent run-on.
I usually just shut the gas off to run
the carb dry......just remember to turn the key/switch
off when it stalls.

In an engine with an updraft carb, you're really not "dumping" gasoline into the cylinders when you close the choke. It's not like a downdraft carb, in which gravity sends the extra fuel directly to the cylinders.

But you already know that.

Dieseling on shut down can be a problem at times IF the ing. timing is off or if your trying to run to lean or if the curb idle is to high and if you do not allow cool down. Or if she is usen a little oil as this is causing some carbon build up . Most of you are just playing with these old tractors and ya are not working them hard enough to burn off the carbon build up . Then ya run the cheapest gas you can buy because you think your saven a couple penny’s . Ya don't believe me when i try and tell ya that this 87 octane gas burns way hotter then the gas of yesterday. Then ya have to stop and think here about your TOY and how old is it ????? . And what has been done to it over the years , how many times has that head been milled down , what has been done to the deck of the block then ya want MORE POWER so ya stuff in better pistons . What is the dist. doing for timing , what advance curve does it have . where is the total advance setting at . Can you get it to run slow enough that ya can almost count the fan blades ???? If it does not want to idle down quite wright then take a look inside the gov. , if the spring is flopping around in the two arm holes then guess what , the bushings are GONE as the spring is suppose to set in bushings and 98% of all the gov. i have worked on they are GONE . The org gov. arms had a hardened bushings that were pressed in and they had a bevel on both sides . The spring also shoved the linkage back to dead idle .Back when thes tractors were new they did what they were suppose to do , but when the new models came out and the neighbor got his new S/M and you still had your old M you would have a S/M kit put in to keep up with him till you could afford to get that new 450 when it came out . Well he could not buy a new 450 so what does he do he puts a 450 kit in his S/M . With these kit changes not only did you get new piston and sleeves but also new curve kit for the dist. and at times a new jet for the carb. or Joe the mechanic drilled the main jet out a little . Oh and don't worry about lead additives Farmalls have hardened seats . Ya want o make some real power out of your S/M - S/MTA and still be able to work it hard then think about putting in the high Alt. pistons and a straight 450 head cam and intake and carb . , BUT you will whine and complain because you will need to put the best gas you can find in it. Over here in my neck of the woods we still us these old tractors every day on the farms around here . The one neighbor just finished up filling silo or i should say a bag and the monstrous Hp. on the massive chopper was a Farmall 400 and the Whopper chopper was a 717 New Holland and two S/MTA's pulled wagons While over on another Farm they were doing hay and corn at the same time with big Hp. a 966 was pulling a Whoppen huge 2 row I H chopper in one field doing hay and in the corn there was a 806 with a 2 row Fox chopper doing corn and a 400 a 460 and a B and 50 John Deeres pulling wagons and my S/MTA on the blower blowing it up and 80foot silo. We keep the OLD stuff going and as long as we can get parts and fuel to run them we will keep going . Yea there are a few around here that put on the dog and have to have the latest and greatest BUT we were not the ones this spring with two new tractors in the field setting DOA due to computer problems , yea we set out in the sun with out the A/C cab and Stero . I do not have to have a 7000 dollar lap top to figure out why it quit either . When dealing with OLD tractors ya got to stop and think about all the extensive FIELD TESTING that they have gone thru and in reality they are plum slap wore out so if ya want to make them like new it takes a lot more the two gallon of paint and a set of decals ,
. I love the term RESTORE when they really mean REPAINT . I did not RESTORE my S/MTA i repaired it and fixed what was wrong with it like the brakes ( as it had NONE ) i repaired the one headlite with a new bulb and then i repainted it and put a NEW seat and decals and USED IT pulled it and showed it and pulled the Girl Scout float with it for three years. I have had this tractor since June 27 1990 . What does it NEED at this moment , a set of ft. tires a new seat and a PAINT JOB , will it go to the field , yep sure will i would not even think twice about putting it on a one row chopper and working the bag off of it . What fuel do we run around here in our GAS tractors ???? 93 octane . WHY because it works (1) it burns cooler (2) it burns longer (3) plugs last longer and we have no problems with running it . Yes it cost a little more but the yearly cost even with the amount we go thru is still cheaper then repair bills. How much gas do you burn thru your tractor a year 50-100-200 gallon ?? This year we will hit about 500 even may be 600 , John boy goes thru around 6-700 Vernon around 400 as he has the most diesel powered tractors John boy has two diesels Eugene and i have three and four gas powered .

Long story short, it is NORMAL.

There is nothing to get excited about. Nothing is wrong. Nothing is going to explode. There is no dangerous condition to sit up nights losing sleep over.

Every once in a while we get a glut of these, "my tractor doesn't shut off instantly, whatever shall I do?" threads.

Calm down. It's fine. Just wait until it stops moving, then get off.

How did you change the timing of the mag without moving the gov gear a tooth.