Is my float sticking?

About 2 months ago when I first bought my Farmall M, I put a carb rebuild kit in it, because everything was leaking and it didn't run right. Well anyways, afterwards it ran like a dream. But now the last few days I've noticed after I shut it off, all the gas will just drain right out of the carb, until the tank is empty. So lately I've been shutting the fuel off at the sediment bowl, but the problem is when I go to start it, it takes like 2 minutes of cranking over to get the gas into the carb to start it. I'm still new to these carbs on these tractors, but my dad said he thinks it sounds like the float is sticking? If that's the case, how do I stop it from hanging?

Good chance trash (grain of rust, a bit of pipe tape or similar) has caught in the float valve seat so it won't seal tight.

Suggest dropping the bowl then removing the float, needle and seat and blowing it out. Also check for a gas-logged (punctured) float pontoon, a loose float hinge (so float binds on the bowl housing) or a damaged needle/seat.

Before reassembling turn on the gas and let it flow for a few seconds to flush the fuel line.

And make it a practice to ALWAYS shut off the gas at the sediment bowl when done using the tractor for the day. Might save yourself losing a tankful of fuel someday!

Here is a cool tip I learned a while back on these tractors.

To check the actual float level, insure the shutoff valve is closed under the tank. Remove the bottom plug or drain plug from the carb. Find a hose barb fitting that will screw into the carb bowl. Get a piece of clear tubing long enough to loop from the drain plug up above the top of the carb. Turn on the shutoff valve under the tank. Observe the actual fuel level in the carb based on the level in the clear hose.

It should be around a 1/8"-1/4" below bowl gasket. If it is higher or keeps going up, look for a float that is taking on gas, a piece of debris in the float, or a float pivot rod that has slid out and allowing the float to drop.

I have found that the Tisco kits for the H carbs have a float rod that is too short and allows it to slide to the side enough to fall off the other side and the float will become cocked in the bowl. You may have a similar issue on your M carb.

Think of your float just like a toilet tank. Gravity feed systems are VERY sensitive to dirt because there is so little pressure to flush them through

The float if brass could have developed a leak, or corroded the float --to--hinge-- connection so that it no longer aligns correctly in the bowl---a good bump could have knocked it askew, causing it to bind in the bowl, etc

If cork/ replacement/ foam float it could be "waterlogged"

Because it seems to have run OK for awhile, I'd guess the level STARTED out OK, but as above, that could have changed.

Don't fret this. Old carbs are simple, but "stuff happens"

If the float pin is falling out, it is because you didn't lock it in place. That is why one side of the float bracket is slotted. Squeeze that slot together just a smidge until you have to force the float pin through it. That is the only thing there is to hold that pin in place. There is nothing wrong with the float pins in the Tisco kits.

Everything below makes sense to me in regards to the gas running thru the carb to the ground when you are not running the tractor. As JimN beat into me years back...turn off the gas on your tractors when you are done. It just makes sense. What doesn't work for me is the 2 minutes of cranking to get fuel to the carb before it will start. It's a gravity system. Turn on the gas and it is there. With your overflow issue there should be enough gas in the carb to get a start even with the fuel off. I do it every day around here to avoid flooding in cold weather. If it were me I would also be looking for an answer to why a Farmall M that should start in a couple of cranks is not starting in a couple of minutes.

Just comparing it to the stock pin, the kit I had was 3/32" shorter. This allows it to shift to the side enough to drop on one side. I know the side of the bracket you are refering to, I just have never needed to locked the pin in place when rebuilding any carb and never had trouble. The bowl clearance to the side should prevent the pin from moving side to side.

You are correct that on most up-draft carburetors, the bowl is configured to prevent the float pin from coming out, but that concept does not apply to a Farmall H or Farmall M carburetor. The float pin MUST be locked in place. There is NOTHING else to prevent it from working its' way out.

All those tanks have some rust in them. When it drained dry, it carried a bunch of rust with it.

It should fill with gas very fast. I suspect your 2 minute fill problem is rust plugging up your sediment bulb inlet and down pipe. Take it off and blow it all out. Watch out for the little screens.

Your carb may have a screen at the inlet as well.

You may need a 1" or so piece of rubber hose to stick over the sediment bowl inlet that sticks up into your tank to keep the bottom rust from getting in. Check the archives for rusty fuel tanks to look at the various fixes.

Besides a little rust holding the float needle open, it is 5 degrees here and a little frozen water could be in there and icing it up. Add some heet to your gas and especially if you are not keeping the tank full.

Good luck and let us know what you find.

Many years ago back in the days when I had a boat I ran into a similar problem. The manufacturer in his wisdom had placed the tank vent on the side of the boat facing forward. Salt water, spray gets in the vent, non stainless tank, it started shedding rust. Ultimate fix was rotating the vent to face backwards.

Engine was a 4 cyl Chevy with a Rochester 2 barrel in it and started having flooding and hard starting problems. Then suddenly it would only run at idle or a little off.

Answer was little globs of rust had migrated through the fuel pump and were holding the float valve partially open and choking off full fuel flow. A lot of effort to fix this. Including pulling, cleaning and and re-coating inside of tank, figuring out where water was getting in in the first place (one was NOT happy when I found that), but I also added an inline filter just ahead of the carb. That got changed out at the annual spring tuneup and cut open just to see. First year I still got some chunks out of the filter. After that it was smaller stuff but there always was some debris in there. Problem cleared up permanently after that.

Just a piece of personal experience along the lines of your problem.
Untitled URL Link