D1305 runs great till worked. Starts to misfire cyl 1

Al Janssen

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Equipment
Zero turn Kubota
Jun 25, 2026
1
0
1
Wainfleet Ontario
Unit starts and runs nice. While mowing, after maybe 5 to 10 minutes, starts to misfire on cyl 1. Verified by cracking injector lines and cyl 1 is not contributing. Replaced that injector. Bled fuel system and unit starts and runs nice. Cut grass for 5 to 10 minutes and starts to misfire again. Retest and cyl 1 again. Could it be the injection pump?
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Yep it could be that or it could be a compression issue.
Do a compression test first as it's cheaper than a rebuild on the injection pump.
If you do remove the pump, save all the shims under the pump as they are critical for the timing.
 

whitetiger

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Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
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Kansas City, KS
Check your valve lash (with the engine cold). You may have too little lash, keeping the valve from seating when at operating temperature.

Check the coolant level in your radiator, not just the surge tank.
 
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