Farmall H surging under load

badfarmallh

New User
OK guys looking for some words of wisdom here, I have a 1948 H. And I cant get it to stop surging under load, the linkage from the throttle lever to the gov housing is in good shape, I took all the play out of it, checked the stops on the gov. adjusted per the manual, the weights move freely, and the assembly slides back and forth. I see posts on here about fuel issues, so ... fortunately I have second H. I swapped carbs and the problem did not change at all. I really think I am missing some type of issue in the gov. I also have installed a rebuilt distributor, checked timing and advance, and everything seems to be working well. Id like any ideas, im out of both good and bad ones.
 
The fuel supply to the carb, and the connection to the tank, and the vent in the cap were not mentioned in your post. Governors react to poor fuel flow by surging. I would start there. Jim
 
ill double check that jim, I did check the flow to the carb, and it seemed more then enough, I haven't checked the vent yet, but being that it leaks a little, I would think that there is enough vent action, I had a surging problem with no load, but was able to correct that through the adjustment of gov and throttle linkage, im getting closer, just not there yet
 
Ethanol fuel is leaner burning than the fuel the H was born for. The load adjustment might be turned out a little to see if it will help. Low float level can also provide lean condition, (but you checked that). The fuel flow needs to be a solid stream running for at least a minute. There is also a screen in the fitting at the carb. Jim
 
Welcome to the H world. I'd make sure you have the tall gas cap, the newer one that IH provides free. The old gas cap might let airout / ventout, butmight not admit air.
Here's my H carb procedure;

Make sure the float isn’t sticking or touching the insides of the float chamber. Some previous advice was to use a Dremel tool and smooth the insides of the float chamber so the float doesn’t rub or touch. Pretty important.
Set the float so the top of it rests 1 27/32" above the flat surface of the float chamber.
Initial settings are as follows to get it started;
Main fuel adjusting screw, big screw facing down at an angle, towards the rear, at the bottom of the carb; 2 1/2 to 3 turns open. This main screw turns clock-wise for leaner mixture. [This screw adjusts fuel.]
Idle air-mixture screw, smaller screw facing forwards, on upper left-hand side of carb; 1 to 1 1/2 turns open. This idle screw turns counter-clockwise for leaner. [This screw adjusts air.]
Idle speed screw, faces outboard, at the top of the carb; set for 450 rpm, and make sure the governor correctly engages in the slot. [This screw adjusts RPM’s.]
Final settings are determined as follows;
Get the engine warmed up, and idling.
Turn OUT the idle air-mixture screw until rough running, then turn in until it idles smooth. (Mine is set at 1 turn open.)
Rev it up, wide open, warmed up, then turn the main fuel adjusting screw IN until rough, then out til smooth, then 1/4 turn to 1/2 turn further out. (Mine is set at 1 turn open. Other advice has been to set it at 2 1/2 turns open for pulling implements.)
Should rev up smoothly and evenly.
Too Lean = stumble, sputter, damaged melted plugs.
Correct = tan plugs.
Too Rich = back smoke, black sooty plugs.

Speaking of H's, make sure you get a new seat spring; those old 65-year old ones snap in half, and you get dumped and get bad hurt.
 
well this morning, i tired to run it without the cap, removed the sediment bowl, checked the screen above it, removed the line to the carb, and founf nothihng, i also removed the plug from the side of the carb and had plenty of flow, and also tried the carb from my other H. and the same problem still exists.
 
well after another day of working on it, this is what I found, when im driving it and it is surging, and I apply the brakes the surging completely goes away and the tractor never misses a beat. I have a new gov spring ordere, im hoping this helps, ive checked everything else mentioned here. I tried a couple different springs today with varying results. I wont be able to get back to it until the 2nd of feb.
 
Sounds like everyone is saying fuel I'll throw a wrench in the box. How's the air flow? Try changing the oil in the air cleaner. Had an A once we were trying to get put away for winter on a cold day. got it to start put had no power, then pulsed some when warmer , jiggled the air cleaner it perked up. Removed the oil bowl from air cleaner ran fine. It was iced over water. Yours might not be iced, just too DIRTY.
 
Another thing to think about are you sure its the engine? Might be clutch. If the clutch holds and slips occasionally, the gov. may respond when it drives again. If you notice a loss of drive/traction, yet engine stays fairly steady(maybe governed perk) check the clutch adjustment.It could slip fast enough not to even notice loss of drive. Just another shot in the dark.
 
Cory,
The clutch is brand new, that was done as part of the work im currently doing, new clutch works great! Im happy with that part of the project
 
Cory,
Ive tried that also, I tried running the tractor with the air inlet to the carb removed and had yet the same results.
 
That's good to know, I was wrong on both counts. They were just guesses anyway since you didn't mention that in the first place, if you did I missed it.
 
The title indicates load, and My (as well as others diagnoses) was based on that idea. Variability while moving is for sure a symptom of governor issues. I am glad it is narrowing down. Jim
 
Surging under load and not under load are two totally different situations. Sounds like it is when not under load which is not unheard of on an H. In fact, IH issued a surge button that can be added on problematic tractors. In fact, my 45 H has one. Dad bought the tractor new and I have no idea if it was on it when he got it or not but it has always had it as far as I can remember.
IH always referred to it as hunting, rather than surgeing. Same thing. A new spring will not help unless your old spring is wrong one and is too heavy. The stronger the spring the more tendency to hunt if the hooking points of spring are the same. Some engines have different positions to hook a spring and that gives you some control over the hunting. Ideally, a very active governor will hunt once or twice when going from low idle to full throttle. That tells you it is very sensitive to change in load. If you have excessive hunting I would bet it is your linkage between governor and carburetor starting down inside governor. Just a slight bind or misalignment will set them off. If you have not checked the adjustment between governor vertical link and horizontal tube to carburetor I would do that. Pull pin, open throttle, pull up on lever going to carburetor so butterfly in carb is fully open and adjust link so pin just freely goes into clevis. Also, loosen the two screws securing tube at the governor so it can seek it's own alignment then retighten.
Hunting under load is normally a fuel related issue.
 
Jim
I know the title is strange, but what it does is hunt under partial load, and not at all under a full load, if that clears it up, ill be back at it monday
 
well it hunts under partial load but not at all under a full load, I did check the pin on the throttle linkage, and the rod from the gov to the carb moves free. I didn't loosen the screws and let it self align when I was done, but I can do that, ive had the carb off a few times and nothing changed when I put either carb on and the rod always moved free, but I will check it again anyway.
 

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