MF 135 Gas From Tank to Carb Issues

[slhilbert]

My MF 135 seems to be having trouble getting the gas from the tank into the carb. This has me completely puzzled and I have no idea why I am only getting a very slow trickle of gas out of the tank to the carb.

Here are the things I have tried.

1. Replaced Fuel Line
2. Removed Inline Fuel Filter
3. Removed Sediment Bowl and made sure all connections were clear
4. Drained Gas Tank looking for sediment, found none
5. Flushed out gas tank with a ton of water, it flowed freely without issue. Then dried it out with compressed air for three days
6. Removed fuel gauge float and tried probing the tank with a long rod, the result is that as I was probing some more gas would flow then normal
7. Removed cap, in case of vacuum

None of this has made a different, does anyone have any idea what might be the issue?

Thanks,
Stuart
Indiana

 

[WilliamTO-35]

You've certainly covered most of the problem points . I'll just list all of the similar fuel flow problems I've dealt with ; New sediment bowl/fuel shutoff was made in China , and fuel passages were not drilled at all. The screen attached to the top of the sediment bowl/ shutoff assembly that goes into the tank was clogged . The fuel filter inside of the sediment bowl was clogged. An air lock inside of the sediment bowl prevented flow. Loosen the bowl and let fuel drip down for a while until the bowl is full of fuel. The shutoff knob had a normal and a reserve position, and only flowed in one of the two positions. The glass bowl gasket was oversized, and blocked the fuel flow. The inline filter was too fine, and clogged easily. The fuel tank contained a very fine, white sediment that would flow through some filters, but would accumulate inside of the carburetor and clog the idle circuit. ( Installing a large spin-on 10 micron filter solved that problem). I believe the white sediment was the lead based terne coating inside of the tank that was corroded by ethanol in the gasoline. Good luck with your problem !

 

[Jerry/MT]

My MF 135 seems to be having trouble getting the gas from the tank into the carb. This has me completely puzzled and I have no idea why I am only getting a very slow trickle of gas out of the tank to the carb.

Here are the things I have tried.

1. Replaced Fuel Line
2. Removed Inline Fuel Filter
3. Removed Sediment Bowl and made sure all connections were clear
4. Drained Gas Tank looking for sediment, found none
5. Flushed out gas tank with a ton of water, it flowed freely without issue. Then dried it out with compressed air for three days
6. Removed fuel gauge float and tried probing the tank with a long rod, the result is that as I was probing some more gas would flow then normal
7. Removed cap, in case of vacuum

None of this has made a different, does anyone have any idea what might be the issue?

Thanks,
Stuart
Indiana

It looks like you have checked most of the upstream places for blockage. Have you removed the sediment bowl/ fuel valve assembly and checked that for blockage? There is a little disc filter in some of these units. Our TO-30 has two outlets from the tank contained within the valve/sediment bowl assembly and one is higher than the other. The taller one is for normal fuel flow and it is open at two turns of the fuel valve knob. The other is for reserve fuel and you have to open the valve wide open to get fuel flow.Have you checked the tank outlet tubes for clogging? If you remove the fuel line at the carb are you getting a large volume of fuel? If you are then have you checked the filter at the carb inlet elbow?

 

[MatthewPaul]

I had to clean the fuel line and fuel valve in mine, and every few days I will have to take the fuel bowl off and blow compressed air up through the fuel valve into the tank, as I slowly open the fuel valve. There must be something in the tank which is covering or clogging the inlet for the fuel valve - that does not come out when cleaning the tank out. Perhaps your 135 has the same issue as mine. When you open the fuel valve with an empty glass, does it fill quickly or just kind of take its time filling up? When clean mine will fill in a 4 count. When clogged it will take 15+ seconds to fill.

 

[slhilbert]

I got it working!

We have had so much rain that I haven't been out on it. The clouds broke yesterday for a few hours so I hopped on and tried to do what I could in the field. Fuel started to become a problem and I remembered what one of you said regarding the sediment bowl being on too tight.

I shutoff the fuel from the tank. Removed the sediment bowl, dumped the contents and put it back on. I put the bowl back on and I could see the fuel was just trickling out. I loosened the sediment bowl and boom-shaka-laka, fuel was gushing out of the tank.

I appreciate everyone's response I think I would have explained away that as a solution in my head if I hadn't read it here.



Thanks,
Stuart