I had the same problem with a marinized Kubota 2 cylinder z500. Have been working on the injection timing for weeks. Put in new pistons, rings, bearings, and rebuilt injection pump. When doing the timing I was basing the firing timing on when a bulge of fuel is visible but the correct approach, according to the manual, is to set the throttle to full, make sure its bled, then look for "the first sign of fuel movement". When I dried the injection pump port with the tip of a paper towel and looked for the first sign of fuel movement the timing mark got closer. I added another shim to make a total of 4 shims and she was timed perfect. Summary - set the decompression lever, dry the port, then rotate really slowly, there is a several degree difference between "first sign of movement" and the fuel bulge you see people talking about in this and other few videos out there. Hope this helps.
Apparently there as some very thin shims that are prone to sticking to the mating surface between the pump and housing...I believe they are used to adjust timing.
Yeah you could be off when you put the motor together originally I wouldn’t know but I do know that I never went off the fly wheel for any markings I just took everything on the front line every mark on the front gears and always had good luck.
![Kubota V2403 Injection Pump Timing Adjustment [Diesel RHD TJ Wrangler - 61]](/img/n.gif)
I had the same problem with a marinized Kubota 2 cylinder z500. Have been working on the injection timing for weeks. Put in new pistons, rings, bearings, and rebuilt injection pump. When doing the timing I was basing the firing timing on when a bulge of fuel is visible but the correct approach, according to the manual, is to set the throttle to full, make sure its bled, then look for "the first sign of fuel movement". When I dried the injection pump port with the tip of a paper towel and looked for the first sign of fuel movement the timing mark got closer. I added another shim to make a total of 4 shims and she was timed perfect. Summary - set the decompression lever, dry the port, then rotate really slowly, there is a several degree difference between "first sign of movement" and the fuel bulge you see people talking about in this and other few videos out there. Hope this helps.
Very interesting ! It's the only video on UA-cam which explain the Kubota timing injection pump
Apparently there as some very thin shims that are prone to sticking to the mating surface between the pump and housing...I believe they are used to adjust timing.
reduce shim thickness in that inj. to get it to fire sooner?
Hi did you solve this problem I am having the same issue?
yes bad fuel camshaft!
What measurements did you get to check this? I can’t find the cam specs anywhere
Yeah you could be off when you put the motor together originally I wouldn’t know but I do know that I never went off the fly wheel for any markings I just took everything on the front line every mark on the front gears and always had good luck.
D850 falinger nambar
THE LOBES ON THE FUEL CAMSHAFT AN THE LOBES ON THE PUMP WHERE WORN......
Thanks for sharing the cause of the problem 💪💪💪