MF 231 random fuel starvation issues.

[Grant31781]

I have a strange fuel issue going on. Some days the tractor will gradually start losing rpms from idle around 1100 rpm or less and pick back up or either die. When it does die, it is hard to start. The engine is turning over fast like it is sort of running with the starter keeping it going but not enough fuel to stay running.

While idling, It will also lack any throttle response. Push the pedal down and it barely responds.

The strange thing is at 2000 rpm when working the tractor, it doesn't have any issues. I would expect this to be more of an issue under load.

I installed a new lift pump because I though it might be the issue. Didn't help it. When I had the pump off the fuel flowed freely from the tank line.

The tractor does not do this every time I use it. There also seems to be a correlation with this occurring when the tank is low on fuel.

The fuel filter is not old has very little hours on it.

Any ideas on how to fix this would be appreciated.

 

[Dmacleo]

governor or shut off cable (didn't 231 use that?) issue?
the ok at higher rpm is also where I would expect fuel starve issues (pumps/line collapse under suction/etc) to happen.
don't suppose the fuel shutoff valve is acting up? just a wild guess there as I don't know where its located in relation to lift pump.

 

[can do]

I have a strange fuel issue going on. Some days the tractor will gradually start losing rpms from idle around 1100 rpm or less and pick back up or either die. When it does die, it is hard to start. The engine is turning over fast like it is sort of running with the starter keeping it going but not enough fuel to stay running.

While idling, It will also lack any throttle response. Push the pedal down and it barely responds.

The strange thing is at 2000 rpm when working the tractor, it doesn't have any issues. I would expect this to be more of an issue under load.

I installed a new lift pump because I though it might be the issue. Didn't help it. When I had the pump off the fuel flowed freely from the tank line.

The tractor does not do this every time I use it. There also seems to be a correlation with this occurring when the tank is low on fuel.

The fuel filter is not old has very little hours on it.

Any ideas on how to fix this would be appreciated.

Hey Grant31781! I take it she is a diesel ? Sounds like You might have debris , or dirt in the tank & it collects where the main feeder line goes to the filter & when your low on fuel it restricts the fuel flow & is your fuel tank over the engine?Next time your tank is is almost empty candle it with a good led light & look to see where the line drains down , If it's a gravity fed tank & even if it's not. I think IMHO this may be the source of the problem& also check for water in the tank.& again IMHO it's between the tank & the main line from the tank. If You find the source please let me know, I would like to know & I'm sure other TBN members do to & good luck.

 

[can do]

I have a strange fuel issue going on. Some days the tractor will gradually start losing rpms from idle around 1100 rpm or less and pick back up or either die. When it does die, it is hard to start. The engine is turning over fast like it is sort of running with the starter keeping it going but not enough fuel to stay running.

While idling, It will also lack any throttle response. Push the pedal down and it barely responds.

The strange thing is at 2000 rpm when working the tractor, it doesn't have any issues. I would expect this to be more of an issue under load.

I installed a new lift pump because I though it might be the issue. Didn't help it. When I had the pump off the fuel flowed freely from the tank line.

The tractor does not do this every time I use it. There also seems to be a correlation with this occurring when the tank is low on fuel.

The fuel filter is not old has very little hours on it.

Any ideas on how to fix this would be appreciated.

Hey Grant31781 I found this post from a member dated 5/23/2018 with similar issues with his M-F 231 it was posted by member nedmax 5/23/2018 This may be the problem? It's worth checking out .& it's on TBN.

 

[Grant31781]

I think it is fixed. Been idling at 800 rpms for 15 minutes. Throttle response is great. Idle is dead steady.

I drained the tank. It had 5 gallons of diesel in it. Fuel looked and smelled fine. I removed the fuel valve from the tank and the plastic line going from it to the lift pump. Took a bath in diesel yeah!

My valve did not have a filter in the tank. The 1st thing I noticed was a ring of a sticky wax like substance in the opening. I disassembled the valve and found the tapered tip of it was coated in this waxy substance along with the bore of the valve. I cleaned the valve out with some drill bits. The valve will not shutoff even clean. No big deal.

I also shot brake cleaner through the plastic fuel tube. I felt the tube jump a few times like it was shooting out clumps of that crud.

I also added a 1 inch long vinyl tube to the valve to raise the pickup point to hopefully help not picking up crap on the bottom of the tank.

I tried to look in the tank. It was impossible to see back where the pickup is. I did stick my finger in the hole and got rusty diesel on my gloves. I couldn't really see or feel anything large or sticky in the tank.

 

[can do]

I think it is fixed. Been idling at 800 rpms for 15 minutes. Throttle response is great. Idle is dead steady.

I drained the tank. It had 5 gallons of diesel in it. Fuel looked and smelled fine. I removed the fuel valve from the tank and the plastic line going from it to the lift pump. Took a bath in diesel yeah!

My valve did not have a filter in the tank. The 1st thing I noticed was a ring of a sticky wax like substance in the opening. I disassembled the valve and found the tapered tip of it was coated in this waxy substance along with the bore of the valve. I cleaned the valve out with some drill bits. The valve will not shutoff even clean. No big deal.

I also shot brake cleaner through the plastic fuel tube. I felt the tube jump a few times like it was shooting out clumps of that crud.

I also added a 1 inch long vinyl tube to the valve to raise the pickup point to hopefully help not picking up crap on the bottom of the tank.

I tried to look in the tank. It was impossible to see back where the pickup is. I did stick my finger in the hole and got rusty diesel on my gloves. I couldn't really see or feel anything large or sticky in the tank.

Hey Grant31781! You need to have your shut off valve working, Check your oil level before starting to see if it has risen if it has do not start your tractor & drain your oil asap,If the shut off valve is left open for to long without the engine running it will allow the fuel to overflow into the block/crankcase! Quick fix disconnect fuel line prior to shut of valve & plug the line & replace shut off valve asap.

 

[Grant31781]

On a diesel? The shutoff valve on the tank has never been closed on the tractor since we owned it 20 years. Never had fuel in the engine.

 

[can do]

On a diesel? The shutoff valve on the tank has never been closed on the tractor since we owned it 20 years. Never had fuel in the engine.

Is there a 2nd shut off prior to fuel pump ? & yes I was referring to a gravity fed gasoline tractor! but if You have a fuel pump prior & have not had any problems , Then I would not worry about it but if it where mine I would make sure everything is working properly & there is a reason for a shut off valve or the manufacture would not have installed one, Just saying glad to hear she is running good .

 

[Agvg]

Check if you are missing a strain on the top of the fuel valve.