1940 Model H Carb issues

Hello, I am new here and a new to Farmall ownership (I did have an old IH panel truck back in the day).

I am have some carb issues, and thought I poll the group here for advice.

It is a gas engine, converted to 12v. Engine starts and idles fine. Really sounds good, however when I put a load on it, or rev it up, it seems to load up and kill the engine. It starts right back up, and again, seems to idle fine, but I keep having intermittent cut-out and the engine seems to choke. I changed the fuel filter, but it did not seem to help much. The problem seems to be carburation. Any advice on where to start would be greatly appreciated.

Hi....welcome...Im no expert by any means.... you will receive some good answers soon; I have one also and had some issues but ok now; as for yours , is it "flooding out" and dripping gas when it dies or is it starving for gas?

No fuel coming out of carb, as far as I can tell.

sounds like the gov isnt working the linkage from the gov to the carb needs to be checked. If the carb didnt work it just would not start and run

try choking it when it starts to bog down

Trying to diagnose online is difficult because we often use different words to describe a problem. Normally, when we say an engine is loading up, we mean it is getting excess fuel, smoking black etc, like you were using excessive choking on a normal running engine. If it cannot get enough air through air cleaner it will also idle fine but LOAD up, smoke black when increasing rpms or adding a load. When and engine dies out so to speak, under a load, I just say it wants to DIE. Some call it bogging down which , being a mechanic for over 60 years now, never heard of that term until I got on the internet. Spit and sputter, miss fire, coughing, back firing all terms people use so it can be tricky trying to solve the problem.

The first thing I would do is observe the exhaust. Does it get black from excess fuel when you speed up the engine. If it does not, I would try turning the main jet adjusting screw out on the bottom of carburetor. Screw with a packing nut on it. Normal setting of that main jet varies all over the place depending on what jet is in carb and who has been working on tractor. Normally about 3 1/2 turns out from bottoming is close. I just open the throttle, turn screw in until engine starts to slow or sputter and then turn out a 1/2 turn to full turn.

Now, if the engine labors like you were already pulling a plow when you try to speed it up, you may have an ignition timing problem. Could be spark advance is stuck or broken. Does it have battery ignition or magneto, big difference in finding the problem. Magneto is a fully enclosed unit where battery ignition has the coil mounted on the outside. Magneto supplies it's own electrical power to provide the ignition where battery ign has to have a battery to operate. Confused by now, so am I. Hope this helps some.

Here are a couple things to check-

When was the last time it had a thorough tune up ? I have lots of experience chasing carb issues that were ignition related. See if cleaning the points helps. Run a sharp points file through them and pull the corner of a clean rag dipped in acetone through the closed points. If the points are pitted replacing them and resetting the timing won't hurt anything.

If you remove the float bowl drain plug or open the drain tap (gas vs distilate carb) do you get a steady stream of fuel running out for several minutes ? I think it takes my H 3 minutes to flow 3/4 of a pint of fuel. If the fuel flow is much lower than that there are screens in the sediment bowl and the carb inlet that need to be clean.

Greg

I changed plugs, rotor, distributor, points, condensor, and still have same issues. It starts easy, runs fine, and I will be mowing (for example), and the engine will bog and die. It seems to die more often when I am turning or going uphill, although that could just be coincidence, as my property is mostly rolling prairie. No black smoke, and it starts right back up again. I am going to check timing and those fuel line screens and get back to you all. Thanks for the tips.

there has to be fuel in the carb or it would not run did you remove the drain plug or another one.

If everything else checks out I would take another look at your fuel filter. Originally those tractors depended on the screen in the sediment bowl and another on the inside end of the fuel inlet fitting. If the added filter is not designed for a gravity fed fuel system it may not be allowing enough fuel to enter the carburetor fast enough when the engine goes under load.

(quoted from post at 17:48:04 08/15/17) Hello, I am new here and a new to Farmall ownership (I did have an old IH panel truck back in the day).

I am have some carb issues, and thought I poll the group here for advice.

It is a gas engine, converted to 12v. Engine starts and idles fine. Really sounds good, however when I put a load on it, or rev it up, it seems to load up and kill the engine. It starts right back up, and again, seems to idle fine, but I keep having intermittent cut-out and the engine seems to choke. I changed the fuel filter, but it did not seem to help much. The problem seems to be carburation. Any advice on where to start would be greatly appreciated.

Click to expand...

Changed the fuel filter? Unless someone has added a filter, the only fuel filter on an H is the sediment bowl. I would clean and service the sediment bowl, replace that in-line fuel filter with a piece of hose, and then see what she does. Nothing wrong with an in-line filter, but it needs to rated for a gravity fed system.

I had a similar problem with my M. Try this, with the fuel valve open at the sediment bowl, remove the line from the carb-side of your inline filter. You should get a strong full stream of gas, if you see a trickle or weak flow then you have a constriction caused either by the filter or at the sediment bowl. I have had problems with the opening from the fuel-tank into the sediment bowl becoming clogged where the engine starts and idles fine but cuts out at full throttle and/or dies under load. The passage from the tank to sediment bowl can be cleared with a wire or gentle compressed air.

I wanted to close the loop on this thread.

The problem was indeed carbueration. I gave the beast a complete tune-up, and then we drained the carb. It had quite a bit of water in it, which comes about from ethanol destabilization. I found a local station that sells petrol with no ethanol, and then I am using a couple of additives due to lack of lead in the fuel. She runs like a top now.

Thanks everyone for the tips!