Mowing kubota t1760 dies after 20 mins

[sammy417]

hi folks!

so i have looked high and low on the interwebs and i find these forums describing the same issues as im having but never post a fix or what the issue was...

my kubota has 4500 hrs on it but purrs like a kitten when it starts up. Itll mow for about 20 mins then die and wont start back up after it dies must wait atlest 15-30 mins.When it dies it just shuts down every now and then it will surge but only after it has died the first time and i try to start it up will it start then surge down.

here is what i have done so far and wht i have checked.
pulled the carb cleaned it
replaced the gas
replaced the plugs and regap
new fuel filter
oil filter
gas lines
tested the fuel pump it worked (altho im still skeptical can these things just die randomly?)
i bypassed the thing in the carb cup (it used to not start at all untill i did that)

im about 3 steps away from putting a match in the gas tank plz help me figure out whats goin on here

 

[Gatorboy]

If you fill it up, will it start and run? I'm wondering if the fuel line in the tank broke off. Just a wild guess.

 

[sammy417]

it its fills up nothing wrong with the lines that im aware of
i assumed after being as old as it is it would need new lines so i replaced all gas lines

 

[sammy417]

ok quick update
i believe this issue has to do with the fuel pump...

after talkin to someone i was told to run it untill it died and check the fuel pump. Pump was good before i started it now after it has ran and died the pump does not pump so i ordered one i hope this is the fix i will post later after the repairs have been made

 

[aczlan]

Is it an electric pump, or a vacuum pump?

My first two suspects would be:
1. Clogged vent in the fuel cap (causing a vacuum in the tank after running for a while, test by cracking the cap open after it stalls and see if you hear air go in and/or if it starts right back up)
2. Junk in the bottom of the tank plugging the outlet (test by running till it stalls then disconnect the line from the tank where it goes into the fuel filter or pump (whichever is first) and see if you get a good flow of gas. If you don't (even with the cap loosened), blow some air back up the line and into the tank. If there is junk in the outlet, this can blow it clear).

A possible 3rd would be a fuel line that is falling apart, but it looks like you took care of that already.

Aaron Z

 

[sammy417]

vacuum i assume i dont see any wires going to it

 

[Stratto]

Run a drill through the inlet of the carby. Look in the needle seat to see the end of the drill. When the carby was made the inlet is partly blocked.this only lets a small amount of fuel through and when the fuel heats up becomes blocked. Let the engine cool down 20 min and it will start again, done 3 of these.i not so sure there is a small screen in the inlet.any how drill it out

 

[ozzie tractor]

check the breather hose on the carby. it runs real close to the exhaust and get melted. once its melted it blocks and wont let the carby breathe. it takes about 20 minutes for the carby to build up enough pressure to stop the fuel pump from working (yes pump is vacum pulse and have been know to expire too). get the breather and cut it off @ about 6" so it finishes above the muffler and cant be melted again. spent 2 hr looking for this one day.