So help me out, if you could. IH 300U I have owned for 4-5 years. Bought it at an auction, talked to the son of the owner who said it was "restored". Indeed, they kept it in a heated shop. Looked reasonably nice. My memory is that this tractor started fine in cold weather the first winter it was here. Memory gets a little dim thereafter. Currently, you cannot start this tractor in cold weather. Battery was my first thought but I ran a trickle charger on it last winter and it would not start even if I added jumper cables from the truck. Weather warmed up and she came to life. Floods like a son of a gun if you keep cranking it. Where should I start on this? Would be REALLY handy to have this one running in winter so I could bring the 1520 home to plow snow here.

If it has been convertred to 12 volts and yuu have a resister,try bypassing the resister while starting.

A bypass can be done easily with a wire from the starter side of the starter relay to a diode 4 amp 150piv. with the conductivity away from the starter then to the coil side of the resistor. This allows the bypass without allowing the ignition system from trying to run the starter motor. Jim

Sounds like a good remedy. Thank you.

How do you handle the choke?

Do you set it and forget it, or no choke at all?

I have a 300u with 7600+ hrs on it-been in the family since it had 75hrs.It is still 6v,original starter,and will start at 15 or 20 degrees with the old battery that's in it now.It has cranked very slow since I was 10 yrs old when I would have to load manure with it in the winter on our dairy farm.But,it has always started.I have 00 battery cables on it.I set the throttle half way,full choke,and fires on the 2nd or 3rd revolution,sometimes on the first though,if has been used recently.It is cold natured and needs a lot of choke to stay running at first,but after a few minutes is ok with no choke.Once warmed up,it has plenty of power.I think if you let off the key,while cranking, from crank to run at just the right moment it helps by letting full voltage to the coil.Mark

Cold weather amp draw from the starter is my "first cause" place to look. Voltage at the coil must be above 4.8 v while cranking to make good cold weather "fire" at the plugs (assumes 6v). A list:
Measure voltage at the coil while cranking.
if lower than 4.8, check the voltage across the battery (posts not cable terminals) while cranking. If lower, you might need a battery.
Double those numbers if 12v.
Attempt to start it by using the tractors battery only for the ignition.
Use a jumper cable (2 gauge real jumpers, not "booster" cables), and attach the ground to one of the starter bolts, and touch (in neutral clutch blocked down to reduce trans oil drag) the copper link between the starter relay and the starter motor terminal. This allows only full tractor battery to get to the ignition, and jumper amps to crank it.
Over choking can flood the engine and flooded engines quench the spark by having liquid fuel between the plug electrodes. Gasoline does not ignite as a liquid. Older plugs can sop up gasoline easier than shiny new ones.
Every battery cable should be 00gauge and as short as possible. Running a ground cable from the battery to the starter bolt is another voltage increaser. Any smaller and the distance to the starter will drop voltage radically.
Modern 10-30 oil is another speed picker upper for engine cranking.
They are pretty easy starting engines. Give some of these ideas a try. Jim

If it is still 6v I suggest a transition to 12v.

Thanks Jim! It is a twelve volt I believe. I only hesitate because of the number of things with batteries that I have in the shed. Sometimes I need to look to be sure. I will try your suggestions here as soon as possible. Looks like we are in for some rotten weather again so may be a couple days. I will post back with results.

Much appreciate the other responses also. Don't think I am mishandling the choke. Sorry if I gave that impression. But I will make sure to be careful there.

Do what David G suggests - go REAL easy the choke when cold starting. (Yours flooding says you're using too much choke...)

To cold start, soon as the engine rolls over give the choke a quick blip shut, then IMMEDIATELY back open. If the engine is in reasonable tune it should fire right up. Though you may need some partial choke again (briefly) to keep it running.

Dave, As you know I also have a 300U. I find that mine does not start very good in cold weather either. But if I plug in the block heater for an hour and put on the battery charger, it will start right up even in zero weather. I pull the choke full on and just touch the starter and it's running. It's still on 6 volt. Don't know what to tell you other than to put on a block heater as mine has the same problem. Also, mine seems to start better if you keep the throttle closed when starting it. Someone once told me that 300s on 6 volts are not good starters in cold weather. One thing I was going to try was to direct connect a 12 volt battery to just the starter with the ignition on the six volt battery and see if that makes any difference. Al

My 300 RC floods easily in cold weather too. I find that I have good results by turning on the gas, pressing the starter button for 2-3 seconds at a time 3 or 4 times with the choke all the way closed and the throttle at about 1/3. If that doesn't do it I turn off the gas at the sediment bowl, open the throttle to 2/3 and open the choke and try a few more times. If it still doesn't fire I give it a 1/4 to 1/2 second burst of ether down the air cleaner. Just about as fast as you can get your finger on and off the button. It seems to help sometimes when nothing else will. Then if I do get it running I have to remember to turn the gas back on.
Zach

Is your tractor 6 or 12 volts. Does it crank over OK or is it sluggish in the cold. I would make sure you have good clean points and use a hotter plug that what is recommended in the manual. On the restore job was internal engine work done. Maybe the valves aren't set right. Your carb will leak gas with a lot of cranking and no start - any Farmall I've ever seen will do that.I'm sure others will have more thoughts.

My H just wants a quick burp of choke even in coldest weather.

Maybe make sure the choke is actually closing.

Says it floods if he keeps cranking.