350 U (The Tractor Vet)

I have a 350U that I would like to wean on gas comsumtion. I use it manly for parades and shows.
Just seans like it uses a lot of fuel. About all Iv"e done is screw in main jet till it starts missing and back a touch. Tractor Vet. read the post about the gas 460/806 tractors and sure wish I would have known some infor years ago, like they say you are never to old to learn, 76 plus and I am.

Just keep in mind that lean is mean . and when the engine is not getting what it needs then the gov. tells the throttle plate to open wider . Tune it like your going to work it . Go thru every thing and be dead on with all your settings . Pay close attention to valve set and look at the wear on the rockers , Don't try and get the whole feeler gauge between the rocker arm and the valve stem as this gives a false reading and set . Check the timing of the engine and make sure that the advance is working . As to setting the carb myself i would set it at 4-4 1/2 turns off the seat and get the ideal set as low as i could and get it as smooth as i could then set it back up to the correct ideal RPM's setting a carb is sorta a knack that comes from just doing it .. Is your carb wore yep more then likely comes from to much field testing when new. Everybody worrys about how much fuel they burn . A tractor will burn fuel they were not fuel sippers . Ya want something that sips fuel then get a Old 400-450 Diesel or a 720-730 Deere a David Brown . look at the size of the fuel tanks and that will sorta tell ya how much fuel a tractor will eat in a day , all but and old M that we had put twenty gallon in at the start of the morning of picking with a two row mounted and it would tell ya when it was lunch time as it was out of gas. Put twenty more in it and it would tell ya when it was time for supper . She would suck down twenty gallon in four hours five gallon and hour picking corn .

Tractor Vet, thanks for your reply. We had a 300U for several years (57-80) pulled a 6 row (narrow) corn planter and had a rear 2pt culivator. Baled many a bale with a 46 IH baler. Just don't remember it using that much fuel.

Unless you find an obvious leak, or someone siphoning it out of the tank at night, there's nothing you can do about fuel consumption. They drink what they drink, so either feed 'em or don't run 'em.

Even leaning the carburetor to dangerous levels won't change fuel consumption all that much. You can buy an awful lot of $4 gas for what it costs to rebuild an engine.

If all you're doing is parades and shows, how much gas are we REALLY talking about here?

A Cub makes a nice fuel efficient parade/show tractor all around.

my 300u uses less than my 48 8N???

I have an H, a 300U, a 340U, a couple of 8N's and the bigger tractors. I fully agree, the 300 U is a thirsty beast. But it does put out the power when needed.

My theory (and I may be wrong). The 300 U has a carb the size of an M carb (large bore) put on a 164 cu inch engine. The H has a much smaller carb put on a 152 cu inch engine. Both engine designs are similar, neither is high tech. The H gives a lot of pull power, and may rival the 300U, but the comparison is not quite fair with the difference in wheel sizes and parasitic losses from the FT hydraulics of the 300. But due to the similarity in cu inches, the CFM of air/gas going through the carb is similar, but the smaller carb of the H gets the air flowing at higher velocity, so it does a better job of atomizing the gas. The carb on the 300 is made for a M engine of ~269 cu inches, so it has a relatively low velocity of air flow in the 300. Thus the gas is not vaporized well, but gets sucked down in bigger droplets. My 300 has always run smokey compared to the H.

Now the experiment, based on the above.... can you physically mount an H carb on the 300 engine? If so, I think you will have better fuel/air mix and thus lower fuel consumption, but not quite as much gut pulling power.

Compare the 340 U with its 135 cu in engine. Much better fuel economy, but this is a newer generation engine (with a small carb like the 8N Ford has). But I'll admit, it does not have the pull power of the 300 U. I do think it has higher compression, and a more agressive spark advance curve in the dist. For small farming and considering the cost of fuel, I prefer the 340 U, although it is not as stoutly built as the 300/350's.

FWIW..

Paul in MN

I, too, am frustrated by the gas-guzzling 300U. I put in 5 gallons, go up and down the lane, maybe pull some wood out of the pasture (in other words, no hard work), and after an hour it is out of gas. Rebuilt the carb, but that didn't change anything.

"look at the size of the fuel tank..."

I'd hate to see the fuel bill for a big 4 wheel drive!

karl f

Oh yea I have run some big equipment and burnt lots of fuel in a day . The time i spent working in the oil patch around here running 750-850 Deere Dozers and D6D Cats 80 -100 gallon a day and sometimes more When i worked construction the D9G would suck down over 250 a day .

Does not seem t be any rhyme nor reason to which ones use fuel and which are economical. Dad had a '50 C that he could use all day on way less than a tank of gas. Got a Super C and it would use a tank and a half for not that much increase in power (this was cultivating corn or beans). We had a JD 60 at the same time as the SC and they used the same amount of fuel per hour for 1 1/2+ times the work on the JD (2x14 vs. 3x14 plow w/JD going a little faster) and the SC used more fuel plowing.