Farmall A starts hard

dahlin · Feb 4, 2012

We have a 1940 Farmall A I've had it for about a year and a half. We put on a new carburator, new plugs and plug wires. Had the magneto off and cleaned and checked. It checked out fine. The tractor when it's cold won't start. Wants its started and warm if you shut it off it will start right up again. When you drive it down the road it has good power and does not miss a beat. I did a compression test with the engine at operating temp and all four cylinders tested out to be 90 PSI. I then did a wet test and the results were just about the same. I'm stumped as what could be the problem. Need HELP!!! Thanks for your help. Randy

teddy52food · Feb 4, 2012

How much are you using the choke. If it smokes black when it starts, you are choking too much. Try leaving the switch off & give it full choke for 1 or 2 compressions. Then open the choke, Turn the ign on & it should start right up. How cold is cold? Below freezing or below zero?

Greg K · Feb 4, 2012

Sounds to me like a timing issue, maybe the mag was never on in the right place, so when you re-installed it the problem didn't get fixed. I have a B and a C with the same motors, and they always start just fine cold, maybe even start better cold than hot.

Janicholson · Feb 4, 2012

If it turns slowly, I recommend two solutions.
(assumes a fully charged good battery)
Put 0gauge cables on it from the battery to the
frame (preferably at the starter motor mounting
bolt), and to the starter switch.
Cables make the difference on 6 volt, listen to
others on here, not at the parts store.
Use 15-40 diesel grade oil in it, or 10-40
automotive grade oil. These will enable it to turn
easily and are appropriate for the tractor. Jim

fixerupper · Feb 4, 2012

Or the gears inside the mag are out of time 1 tooth. Ask me how I know! Jim

CNKS · Feb 4, 2012

2 gauge cables work fine for me, and are easier to bend and install in a rather cramped area if you have the battery in a box. Make sure the battery will hold a charge or get a new one. Clean the battery connections and all places where the cables attach. The connections are more important than the cable size. Assuming that you installed the mag correctly, put the #1 piston at TDC, push the top of the mag against the block, the pull it out until it trips. When cold, turn the starter over, pull out the choke for 2 or 3 revolutions, then push it back in. Any more and the engine will flood. Pull out the choke slightly after it starts to keep it running. Also, go to Walmart and buy a battery maintenance thing to keep the battery charged--$20.

El Toro · Feb 4, 2012

Are you sure that impulse coupling is snapping
when trying to start the engine? It gives a hotter spark when the impulse coupling snaps. Hal

Anonymous-0 · Feb 5, 2012

I did have my mag all checked out, I timed it by the book when I put it back in. The cam timimg I don't know about because I didn't go into that. The battery was fully charged. The tractor does run excellant wants it starts. I was suspicious of the valve on the choke plate but the spring is working on that also. It does seem to help if you take the cover off the air intake and put your hand over it. Thanks for your responses. Randy

El Toro · Feb 5, 2012

Do you have much suction on your hand? If you don't usually means you have low intake manifold vacuum. We used that procedure when cars and trucks had mechanical fuel pumps. If they would start by holding your hand over the throat of the carb and would quit running once the hand was removed meant a defective pump. Hal

Anonymous-0 · Feb 5, 2012

Yes, it has a fair amount of suction. It does not quit when you take your hand off it runs good. I'm of a time when we used to do that and hoped it would not back fire.

gene bender · Feb 6, 2012

You need to remove the cap on the mag and turn the engine over with a crank to see if the rotor is pointed on the tower when it fires. Just make a mark on the body of the mag where the tower is then remove the cap and you can see if the rotor is lined up on the mark when it fires. There are timing gears for the rotor and if you are off even a tooth it will make it hard to start. I have 7 with mags and they will fire rite upwarm or cold.

Farmall A starts hard

dahlin

Member

teddy52food

Well-known Member

Greg K

Well-known Member

Janicholson

Well-known Member

fixerupper

Well-known Member

CNKS

Well-known Member

El Toro

Well-known Member

Anonymous-0

Well-known Member

El Toro

Well-known Member

Anonymous-0

Well-known Member

gene bender

Well-known Member

Similar threads