# Kubota 5030 losing power after warming up



## Kerry/ 2 saws (Sep 4, 2021)

I have a M5030 SU diesel it started to bog down replaced fuel filter bled lines and it seemed to work fine bushoged for about an hour started to bog down again if left for 30 minutes it would run for a while then bog down.
Checked the fuel tank nothing clogging inlet,fuel drained fine from fuel line after filter,replaced fuel line to fuel pump and from fuel pump to injector pump replaced fuel pump, bled lines and high pressure line ran fine for 30 mintute bogged down till it died.
Any ideas?


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## sixbales (May 18, 2011)

Hello Kerry/ 2saws, welcome to the forum.

Sorry, but we always have to ask... Is your fuel cap vent plugged?

Your injectors have a return line for excess fuel return to the fuel tank. See item 020 on the attached diagram. Make certain this line is open. The engine will not run if this line is blocked.









Try this... When the engine first starts bogging down, with the engine running, crack open one injector line at the injector and let it purge fuel (maybe some air?), one injector at a time. Do same to all injectors.


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## sixbales (May 18, 2011)

Here's a U-tube video. The thing that struck me is the possibility of water (condensation) in your fuel system.


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## Kerry/ 2 saws (Sep 4, 2021)

sixbales said:


> Here's a U-tube video. The thing that struck me is the possibility of water (condensation) in your fuel system.





sixbales said:


> Here's a U-tube video. The thing that struck me is the possibility of water (condensation) in your fuel system.


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## Kerry/ 2 saws (Sep 4, 2021)

As far as water in fuel I looked inside of the tank nothing but fuel I took the fuel filter off nothing but fuel the fuel line from the filter to the pump and the line from the pump to the injector pump is clear nothing but fuel.
I bled the lines again ran it till it started to bog bled the high pressure line 2 times, I blew air through the return into the tank it may have been a little clogged but air flows freely now took the return line loose at the valve on the injector pump blew air all the way back to the tank. The only thing I can do that makes a big difference is to close the return valve on the bleeder for the injector pump it will then smooth out some and gain 300 rpm from a max of 1800 to 2100 still wont run completely smooth and blowing blue smoke.


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## Kerry/ 2 saws (Sep 4, 2021)

And I did check the fuel cap the vent works. I have also replaced the air filter.


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## Kerry/ 2 saws (Sep 4, 2021)

I also drained the fuel tank down to half tank and add 1 gallon of Seafoam, still no change.


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## HarveyW (Sep 15, 2014)

Looks to me like you are getting down the the injectors or the injection pump..


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## Kerry/ 2 saws (Sep 4, 2021)

I had the injectors rebuilt it ran better but still died after warming up. Had injector pump rebuilt and got it back together a couple of weeks ago, There was a long delay in getting parts have run it now 20 plus hours with no more problem.
Thanks for all your help.
Kerry


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