Trouble shooting fuel starvation problems

Dallas Huybregts · Jul 10, 2012

Hey all,

Last week I pulled my gas tank off and found the sediment bowl fitting was totally plugged. I cleaned it out, cleaned the tank and cleaned the fuel line.

Today I made a new gasket for the sediment bowl and put some gas in the tank. Unfortunately I found the same problems, the tractor would run for a minute or so and then quit regardless of choke position.

My next plan of action is to look at cleaning the carb but aside from that what should be my next trouble shooting steps?

Christopher Mikesell · Jul 10, 2012

First, what model tractor is it?
Regardless of the model, I think that you should pull the plug at the bottom of the carb and let the fuel run out into a container for a few minutes. If it slows to a trickle, then the problem is upstream of the float bowl. If this is the case, check the sediment bowl again by removing the glass bowl and letting some fuel run into your container. If you get good flow, then your problem is between the float bowl and the sediment bowl. If you get good flow out of the bottom of the carb, then your problem is probably in the carb. However, what seems to be a fuel problem may actually be a problem with somthing else.
Also, just because you cleaned the tank does not mean that it is clean. Varnish can flake off over time and plug things up badly. Filling a tank with more than a fraction of a gallon can help with this, since the flakes migrate the most when the fuel level is low.

Dallas Huybregts · Jul 10, 2012

Thanks for the suggestions. It's a 1955 Case 410.

Ron Sa · Jul 11, 2012

When I have to unscrew a sediment valve asm from an old gas tractor, I always install a short stand pipe in the assembly: about 3/4 inch tall.

Drill it to the OD of the tubing being used for the standpipe about two dia deep and locktite it in place.

PS: Don't blast shop air into the carb fuel inlet with a blow nozzle until the carb is apart. This tends to colaspe the float. Those aren't cheap!!!

Jeff B. · Jul 11, 2012

I had a 311 that would do that. Ran for just a minute & died. Wouldn't start again for a couple hours, then it would fire right up. Couldn't figure it out till I looked at the other side of the engine while I it was running just after dark. Big blue sparks arcing from the coil tower to the small terminal. I changed the coil wire and it's never skipped a beat since.

Anonymous-0 · Jul 12, 2012

I had this very same problem on TWO Case D's a few months back. On one D, it was carbon build up in the exhaust manifold. On the other, it turned out to be the sediment bowl gasket was leaking air into the fuel line. Start the tractor and watch the gas flow through the glass bowl. If the gasket if bad, the gas will start to bubble and you'll see a drop in the gas level in the bowl. When it gets low enough, the motor will run out of fuel and stop running. When it shuts off, you'll be able to see the bowl filling with fuel again and after a minute or so, the tractor can be started again and it will repeat the same situation. Also, check to make sure vent hole on your gas tank cap is clear. Sometimes they clog up and fuel will not flow. Make sure bowl is seated properly.

Trouble shooting fuel starvation problems

Dallas Huybregts

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Christopher Mikesell

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Dallas Huybregts

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Ron Sa

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Jeff B.

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Anonymous-0

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