Checking out a JD LT133 with a 13 hp Kohler CV13S. It was getting gas in the crankcase. I suspected the mechanical fuel pump. The diaphragm had a tear in it so I assumed this was the issue. I replaced the fuel pump and ran it a few minutes but it was still getting gas in the crankcase. I went to remove the carb to check the needle valve. When I removed the fuel line gas shot out of the fuel line like a fire hose. I quickly put the fuel line back on the carb and then removed the gas cap and a crazy amount of pressure was released from the tank. I cleaned the carb and cleared the hole in the gas cap. I tested it and it ran fine for about 10 minutes and started to die, I could keep it going for several more seconds by choking it. What caused the pressure buildup and could that have damaged the new fuel pump, causing the engine stop issues now?
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Excessive pressure in the fuel tank, gas in the crankcase
- Thread starter arch252
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Export threadbertsmobile1
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According to JD the cap is a service part to be changed "as needed "
There is no mechanism for the tank to be pressurised by the engine
The only vent is via the cap
However if it is blocked then just the heat of the day can cause quite a significant pressure increase in a non vented tank.
They stopped amking the LT 133 in 2001 so it is not a new mower so the old diaphragm could have just died from old age
and the effect of the modern trash called "fuel"
Is the new pump pumping ?
Is the float needle OK ?
Hoe did the mower stop.
Like it was flooding . like it was starving ? gradually or suddenly & would it fire back up stait away ?
There is no mechanism for the tank to be pressurised by the engine
The only vent is via the cap
However if it is blocked then just the heat of the day can cause quite a significant pressure increase in a non vented tank.
They stopped amking the LT 133 in 2001 so it is not a new mower so the old diaphragm could have just died from old age
and the effect of the modern trash called "fuel"
Is the new pump pumping ?
Is the float needle OK ?
Hoe did the mower stop.
Like it was flooding . like it was starving ? gradually or suddenly & would it fire back up stait away ?
The float needle was good, I blew in the intake and air flowed smooth, flipped the carb over and the needle completely stopped the air flow. When it cut off it was similar to running out of gas but choking it kept it running enough to get it to the garage.
The pressure in the fuel system damaged the new fuel pump. I replaced the fuel pump again. With the carb clean and the fuel cap vent hole cleared the problem was solved. Always check the simplest things first. Obstructed vent hole in the fuel cap caused a lot of headaches!
bertsmobile1
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That is amazing and thank you for sharing