MH 20 Not staying running

Mikechri · Nov 2, 2023

I wonder if anyone has a pic of exactly where the fuel line should run on my MH 20? When I got it the fuel line was off
and I replaced it and it seems to run until the bowls are empty and then dies. I know it is a gravity fed carb but the
sediment bowl and the carb are about the same level. So I don't know how the gravity thing is working. IM using the
origonal sediment bowl and I ran 1/4 inch piping to the carb. Also it will only run when the choke is on half? Any
ideas? I know the carb is in good shape because when it runs it runs well, It idles down nice and purrs. but then runs
out of fuel. One last thing. I also replaced the dist. cap and rotor when I bought it. It needed it BAD but the cap
doesn't really fit that well, it rattles and isn't held down very tight. can someone give me the part number to get
another one? Thanks in advance

Jim.ME · Nov 2, 2023

The fuel line should run level, or slope down, from the tank sediment bowl outlet to the carb inlet.
How much gas is in the tank? The sediment bowl and the carb inlet can be about level and work fine as long as the gas level in the tank is above the carb inlet.

With a pint or larger container in hand, remove the drain plug from the bottom of the carburetor and time how long it takes to get a pint of gas in the container. The flow should be an even steady flow after the initial draining of the carb bowl. If it is not there may be material plugging the sediment bowl inlet in the tank.

This post was edited by Jim.ME on 11/02/2023 at 02:29 pm.

DanielW · Nov 3, 2023

I second Jim's suggestion of checking flow out the carb drain for a good period (at least 30 seconds to a minute). You need a good healthy stream, not a light stream nor dribble.

Every week someone posts on one of these boards about a similar issue - tractor runs for minute or two then dies. It pretty much always ends up being crud in the tank blocking or partially blocking the fuel unlet into the tank (or having made its way into the lines): Fills the bowl slowly when it's not running, then when it runs it uses fuel at just a little faster rate than it can fill it a due to the partial blockage and shuts down when it run the bowl dry.

Most of the equipment we talk about on these forums is now at an age where the tanks have a good coating of rust and/or grime on the inside, and the cleansing additives in modern fuel are starting to cause it to strip off and plug stuff up. Time to pop the tank off and give it a good wash with a degreaser, then a rust removing solution, then rinse with water, then dry out with a blow gun, then rinse with WD40 to displace any remaining moisture and coat the surfaces to help prevent future rust.

Tgrasher · Nov 3, 2023

If you don't get a good flow of gas (as Jim stated) unfasten the line going into the carburetor and see if there is any difference in flow there. If not, check the screen in your sediment bowl, old gas forms a kind of snot, for lack of a better word, and it will restrict flow. Do your self a favor and put a 1/8 npt 1/4th ball valve shut off just before the carburetor, sediment bowl shut offs wear out quickly.

used red MN · Nov 3, 2023

I will add this, I am a Farmall guy so I know Farmalls have these and other brands may use them as well. I am talking about a strainer in the fitting that the fuel line attaches to, see link, may also have an elbow on it as well. Just something nice to know that one may be there to avoid some head scratching. Also you say you ..know the carb is fine.. that may or may not be true. Usually restricted gas flow into the carb will allow the engine to run fine a minute or two until the reserve in the carb bowl is used up. If the engine immediately sputters and cannot reach higher RPMs after setting a few minutes letting the carb refill then you have a lean setting on the main fuel screw or the main fuel circuit has plugging in it.
Example carb inlet strainer

MH 20 Not staying running

Mikechri

New User

Jim.ME

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DanielW

Member

Tgrasher

Well-known Member

used red MN

Well-known Member

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