Stumped on Carb

John M · Sep 2, 2019

Its been 2 years now, and no matter what we have done to this carb, it simply will just not cooperate. Its been apart like 6 times, cleaned, gone through, put back together and it still acts up. The stupid needle keeps sticking closed, and it just doesnt get enough fuel. Weve tried new needles and seats, old needles and seat, even one brass we just happen to find. We modified seats, done anything and everything we can think of to do, and it just simply wont stay running. This week it did run for about an hour straight with no problems. (That needle ad seat came from an H.) Now its back to only running a few minutes. We thought the line might be a problem, so I changed all of that this morning, nope. Pulled the bottom off the carb and the needle is again stuck in the seat. For temp measures we rigged up a tank, needle stil sticks. Im seriously starting to think something is wrong woth the top of the carb making the needle sit cockeyed or something. ANy sugggestions before Mr Avery (My neighbor who owns it.) buys a new carb for the thing?

Janicholson · Sep 2, 2019

The two ideas I have might help. #1 the tiny tab of brass that lifts the needle can have a wear spot on it that pushes the needle crooked. It can be filled in, or flattened (or replaced with a new float) to fix this (seen it many times). #2 the needle is too tight, or loose, in the seat, and gets stuck. I have used abrasive paper to polish off the triangle edges to make it looser, and also used needles from different carbs to make it fatter. Cutting off and polishing a dome on the new needle by putting it in an electric hand drill !!! Jim

John M · Sep 2, 2019

Its got the carb from my M on it now and its purring right along. I wish Mr Avery would get something lower to the ground, but he loves his Ms. I have put multiple needles and seats in this carb. The one that worked the bast was from an old H he sold 2 years ago. (The man keeps everything.) It worked fine for about 30 minutes or so. The float I know is good, it was mine. His son is coming down this evening with another carb that will have to be rebuilt most likely, so at least he wont have to buy a new one. I still think something is wrong with this top.

Roger Tomfohrde · Sep 2, 2019

Have you checked the float for rubbing on the side? I have tipped the carb over during assembly with it dry. Guy blew into the inlet to make sure it seats. And then flipped it over to hear if it was moving freely.

Janicholson · Sep 2, 2019

If the top was rethreaded at the seat threads, it could be crooked? Jim

John M · Sep 2, 2019

Yep. Its the needle that keeps hanging up. Ive tore the whole carb down with the needle staying stuck in the seat. Ive bored out the seat, filed down the needle, used other needles and seats, etc. Mr Avery has been running it with my carb for close to 3 hours now, not one hiccup. This old M hasn't ran this long on many years. He used it on and off for his garden since 96 or so, and then started using his H. He sold the H a couple of years ago, and pulled the M out a couple of years ago and its been acting up since.

John M · Sep 2, 2019

Thought about that. It looks OK, but it could just be off enough to cause it bind, I suppose. The seat looks to be seating fully on the body.

caterpillar guy · Sep 2, 2019

Take the needle with the steel tip and with it in the seat tap it with a small hammer to make it fit the seat better and try . At this time it is no loss. There was a guy near here that did that with all the carbs he rebuilt to set the needle to the seat.

Roger Tomfohrde · Sep 2, 2019

So the ones in my 560 have a little spring clip that will pull the needle out if it is too low. At least it should as tightly it is in place.

Gary Mitchell · Sep 3, 2019

After making sure the intake manifold is good I'd probably toss that carb and get another one, however, you might try a cheap, low pressure electric fuel pump. gm

rustyfarmall · Sep 3, 2019

There is contaminants in the fuel tank. Remove the tank and do a thorough cleaning.

John M · Sep 3, 2019

Nope. Its really clean, which really surprises me. I had originally thought a leaf or something was in there, but we flushed it
several times and never got anything out, and the times we have pulled the sediment bulb out there is never nothing in the outlet.
In fact, yesterday when it was actng up, I was able to pull the fuel line off before it died and gas flowed freely. Stuck line
back on and it still acted the same.

John M · Sep 3, 2019

Ms dont have that clip.

rustyfarmall · Sep 3, 2019

(quoted from post at 11:20:55 09/03/19) Nope. Its really clean, which really surprises me. I had originally thought a leaf or something was in there, but we flushed it
several times and never got anything out, and the times we have pulled the sediment bulb out there is never nothing in the outlet.
In fact, yesterday when it was actng up, I was able to pull the fuel line off before it died and gas flowed freely. Stuck line
back on and it still acted the same.

It may look clean, but does it smell clean? Residue from old, stale fuel will cause a needle valve to stick faster than anything else I know of.

D Slater · Sep 3, 2019

Sounds like another carburetor is working okay. Just wondering has the tank been lined? If not a perfect job it can leach into the fuel and stick the needles.

John M · Sep 3, 2019

Nope, no liner. Dont know if you remember it or not, but it was the one sitting on the back side of my barn with the rear axle off.

John M · Sep 3, 2019

Yup. know that well. But we have had gas through it, and different needles and seats in it, and my carb ran just fine on it. Im
convinced it has something to do with the top.

used red MN · Sep 4, 2019

So you say the needle sticks in the needle seat, like not falling out? I would have to do some experimenting with that on my own by trying this. Pull the seat out place it on your workbench and then to simulate the float pressure lay the base of the open end of a 3/4 in. wrench horizontally on the needle while holding the other wrench end. Then if you pick up the needle with the seat in it and invert it has it stuck in there? If so yes something is wrong. I would say some kind of a miss match is going on there. On the other hand was it that gas just did not flow. Have you looked at the screen behind the carb inlet fuel fitting? Maybe it has some fine lint type debris in there, that floats up and plugs it. Then when you open the carb and mess with the needle the gas level in the screen drops down and the fines settle into the lower part of the screen. Then after you run a bit they float up and plug that inlet filter. Do you have the screen in the top of the sediment bowl? That is supposed to do the main filtering of the gas. Just an idea because you say it runs fine with your carb, maybe that is because your screen is cleaner. Not trying to belittle anyone?s knowledge, just trying to pick apart an unusual problem. If in your mind the fuel is clean and this cannot be the problem, that can lead to an issue being overlooked. Following a one track mind down the wrong path has definitely happened to me. Good luck.

John M · Sep 4, 2019

Yep. Hangs up in the seat, and wont come out on it own. It will move fine without fuel, but as soon as you turn the fuel on and the bowl is full, the needle stuck. Gas flows just fine to the carb, and yes the sediment bowl, screen and carb filter were clean. With the carb top on the maniold, gas flowed freely through the carb, and through the seat. The needles we tried all fit the seats fine, no rubbing or binding when dry.

I put mine on and it immediately ran 100% better. As a precaution, I stuck an inline filter on there, saw absolutely nothing in that filter after running it for around 3 hours Monday, and it never missed a beat. Yesterday afternoon, I replaced the top that was on the old carb, after cleaning the whole carb overnight, just for giggles. To my surprise somewhat, the tactor ran perfect. Mr Avery played with it for about an hour and it never acted up. Although we did get a little scared when it ran out of gas. Ill look this top over better when I have time, but for now Im calling it good.

rustyfarmall · Sep 4, 2019

(quoted from post at 03:27:11 09/04/19) Yep. Hangs up in the seat, and wont come out on it own. It will move fine without fuel, but as soon as you turn the fuel on and the bowl is full, the needle stuck. Gas flows just fine to the carb, and yes the sediment bowl, screen and carb filter were clean. With the carb top on the maniold, gas flowed freely through the carb, and through the seat. The needles we tried all fit the seats fine, no rubbing or binding when dry.

I put mine on and it immediately ran 100% better. As a precaution, I stuck an inline filter on there, saw absolutely nothing in that filter after running it for around 3 hours Monday, and it never missed a beat. Yesterday afternoon, I replaced the top that was on the old carb, after cleaning the whole carb overnight, just for giggles. To my surprise somewhat, the tactor ran perfect. Mr Avery played with it for about an hour and it never acted up. Although we did get a little scared when it ran out of gas. Ill look this top over better when I have time, but for now Im calling it good.

NEW needles and seats need to be cleaned with aerosol carb cleaner BEFORE installing. Seems there is a residue on them left over from the manufacturing process, and that causes them to stick. Clean them, dry them, and then a short spray of silicon lube will stop that sticking.

John M · Sep 4, 2019

Used new ones and old ones, even one brass one. They all stuck.

rustyfarmall · Sep 4, 2019

Comes right back to contaminants in the fuel.

WD45Aaron · Sep 5, 2019

Take a ball peen hammer and drill a 1/4" hole through the handle an inch from the end. Get some strong cord and hang the hammer on the side of the tractor such that the head is alongside the float bowl. Take another longer piece of cord, tie one end to the hammer head and the other to the dash. Every once in a while give a tug on the cord tied to the dash such that the hammer raps on the float bowl. If you're working rough ground the natural swing of the hammer will do the job automatically. Problem solved.

rustyfarmall · Sep 6, 2019

(quoted from post at 14:55:28 09/05/19) Take a ball peen hammer and drill a 1/4" hole through the handle an inch from the end. Get some strong cord and hang the hammer on the side of the tractor such that the head is alongside the float bowl. Take another longer piece of cord, tie one end to the hammer head and the other to the dash. Every once in a while give a tug on the cord tied to the dash such that the hammer raps on the float bowl. If you're working rough ground the natural swing of the hammer will do the job automatically. Problem solved.

I like how you think!

Stumped on Carb

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