How to Turn delivery valves on kubota D1305?

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chw

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Jul 15, 2006
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Anybody know how to turn delivery valves on D1305, same pump as more common D1105? Obviously I want to do this for more fuel and obviously I do so at my own risk, thank you!
 
I believe that's just a timing adjustment on those pumps. The fuel screw is lower rear of pump.
 
Gt15

mhuggler said:
What turbo did you put on this d1305?
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I used a gt1544. I ran a rhb31 vz21 for about a year but it was too small, intake temps were too high with it. The gt15 seems to be much cooler but I imagine I will still end up doing intercooler or water injection. The cam am maverick turbos have some really nice small top mounts with built in fan that should work.
 
95cummins5.9 said:
I believe that's just a timing adjustment on those pumps. The fuel screw is lower rear of pump.
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Yessir, you are right, I’ve adjusted the timing shims to advance timing as well as the rack travel screw/bolt and both worked to increase fuel. Only thing I can find left to do to the stock fuel injection system to increase fuel is to turn the delivery valves counter clockwise, just not sure how. I see a lot of reference to this in the garden tractor pulling community but only reference not instructions. I’m kind of scared to try it because it will cause a lot of issues if not done properly.
 
Loosen the hold down bolts and rotate it? If that's how everything is fastened to the pump body. I don't have experience with that particular engine, but most smaller stuff has the pump body casting integrated
 
95cummins5.9 said:
So you've already done injectors?
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No, no injector work yet. I wanted to attempt any mods I can do myself before sending off parts like injectors and pump parts like the plungers. I’ve seen someone on eBay selling bigger plungers. I would still have to disassemble the pump and I’m weary of that after watching YouTube videos of ppl doing it and not putting stuff back the way it goes resulting in different issues.
 
JWhite said:
Loosen the hold down bolts and rotate it? If that's how everything is fastened to the pump body. I don't have experience with that particular engine, but most smaller stuff has the pump body casting integrated
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I think you’re right from what I’ve read.
 
Just out of curiosity is this engine in a tractor? If not, what is it in? What is the goal with it?
 
Meyers Farms said:
Just out of curiosity is this engine in a tractor? If not, what is it in? What is the goal with it?
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It’s in a zero turn mower, a Kubota zd331 with 72” deck, and the goal is fun. I’ve decided to put it to pasture and use it as a spare mower if needed so it’s of no consequence to me if it breaks. Lemme tell you, this thing walks the dog on my two Ferris mowers with the 40hp vanguards.
 
:hehe:
chw said:
It’s in a zero turn mower, a Kubota zd331 with 72” deck, and the goal is fun. I’ve decided to put it to pasture and use it as a spare mower if needed so it’s of no consequence to me if it breaks. Lemme tell you, this thing walks the dog on my two Ferris mowers with the 40hp vanguards.
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I wonder if those other turbos you ran would work on the smaller .9L that comes in the Bx tractors? I thought about putting some altitude compensation on my bx2370
 
JWhite said:
I wonder if those other turbos you ran would work on the smaller .9L that comes in the Bx tractors? I thought about putting some altitude compensation on my bx2370
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I would say the gt12 would the vz21 will for sure it’s just a little small.
 
chw said:
It’s in a zero turn mower, a Kubota zd331 with 72” deck, and the goal is fun. I’ve decided to put it to pasture and use it as a spare mower if needed so it’s of no consequence to me if it breaks. Lemme tell you, this thing walks the dog on my two Ferris mowers with the 40hp vanguards.
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Cool! This sounds like an interesting project.
 
Life for an engine in a zero turn must be different. My B2650 has a D1305 in it and 99.9% of the time I’m having trouble keeping it happy with enough load. It’s a very undersquare engine that has insane torque for it’s size; the only time mine ever sees more than 1800rpm or so is when I need a specific pto speed like mowing grass.
 
mhuggler said:
Life for an engine in a zero turn must be different. My B2650 has a D1305 in it and 99.9% of the time I’m having trouble keeping it happy with enough load. It’s a very undersquare engine that has insane torque for it’s size; the only time mine ever sees more than 1800rpm or so is when I need a specific pto speed like mowing grass.
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Yep, it’s a little monster for sure. From what I understand it’s a D1105 with longer stroke. They rev them to 3150rpm in the zero turns. It had power naturally aspirated I just felt like putting the turbo for the heck of it. I’ve for sure got this little motor at its limits being it’s at 31hp factory so with an added 10psi I’m asking a lot of it.
 
chw said:
Yep, it’s a little monster for sure. From what I understand it’s a D1105 with longer stroke. They rev them to 3150rpm in the zero turns. It had power naturally aspirated I just felt like putting the turbo for the heck of it. I’ve for sure got this little motor at its limits being it’s at 31hp factory so with an added 10psi I’m asking a lot of it.
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This little engine not little “motor” whoops ?
 
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