fuel pressure

[lgreenough]

what should fuel pressure be at carb on MF50 with gas engine?
Tractor runs great when gas tank is full,then stalls when tank gets low. I had tank sand blasted and sealed as I thought problem was foreign matter getting in fuel.Tractor starts right up after a few minutes, runs a while and stalls again.
 

[old]

I do not know the MF50 but I also do not believe it has a fuel pump. Very easy for you to figure out if it has one by tracing the fuel line from the carb to the tank. If you find a fuel pump which I do not think you will then it would be around 7psi but I think it is a gravity flow system like most older tractors and and if so then the PSI would be very low so you likely to have one of the filters clogged out junk in the tank. Sediment bowl should have a scree filter in the top part of it. There also maybe a screen in the tank and if clogged it will cause that also
 

[MKinOntario]

Could also be the fuel cap isn't venting properly and there is a vacuum building in the tank. That's been a problem with one of ours.
 

[Gearhead210]

Correct, no fuel pump on any of the masseys with a gas engine (the older ones that is), just gravity feed. I would check the gas cap vent, or take the line off at the carb and let it "free-flow" back into a gas can for a while, it should never slow down. Might be worth seeing if it is losing spark when it gets hot, typical of a bad coil or other ignition parts

Good Luck and happy new year
 

[mike paulson]

measure your fuel by volume/flow. open fuel line at carb and let it flow, as said it should never slow down and give you roughly a pint in about 30 seconds. thats enough to keep the carb fed and the needlevalve and fload do the rest..
 

[DiyDave]

Look for something floating in the tank, too. I've had bumble-bees, and clover heads, that will float on top of gas, till they get sucked into the outlet, causing the engine stop, then float off again!

Also check your coil , condenser, and ignition switch, if the condition is caused by no spark, instead of no gas.
 

[marloweg]

inline fuel filters will restrict fuel flow also some are so fine that fuel will be restricted unless it's under pressure. if you have a inline remove it or replace
 

[mike paulson]

Hey Marloweg. are there any inline fuel filters that are recomended for older machines? i have one on my mf50 and have often wondered about that...
 

[marloweg]

i use the ones that have a fine screen in them but they are hard to come buy. i have a small supply from back when i sold snowmobiles. the auto type have given me trouble over the years with low fuel flow. i had a ford N9 in the shop last week that would stop after a short time and change filter and it ran like new but the owner had just put a new filter on
 

[old]

You mean 9N don't you or more then likely a 2N which there are more of. Over the years I have found ANY in line filter on a tractor is a problem waiting to happen. And yes I have tried them all. Lawn mower types, motorcycle type car types etc etc. I think the reason the in line filter do not work well on a tractor is they do not get the movement other things get so some how that keeps the flow way down. Plus if you have the 2 or 3 filters that where on the tractor when new that is more then enough filtering and a sediment bowl with screen is super hard to beat
 

[marloweg]

ya 9n
 

[mike paulson]

i just rebuilt my carb and didnt notice any type of screen on where the gasline feeds the carb on my 50? is it missing or is the sediment filter bowl all one needs?
 

[old]

On most but not all there is a screen in the tank that sticks up an inch or so and that is part of the sediment bowl assembly then there is one at the top of the bowl and in some not all a screen in the elbow. If I can I try to have all 3 but some times that does not happen but on most all can be put in
 

[David G]

Try cracking the gas cap loose when it does that. I would also question the lift pump if it has one.
 

[El Toro]

Look inside that gas tank for any crud blocking that outlet. Disconnect the gas line at the carburetor and check the flow from the tank. Use a clean container to catch the gas. Some of the sand may have blown into the fuel tank. Hal