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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 25655
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I'm a tech at a Polaris dealership. I have no experience in

Customer Question

I'm a tech at a Polaris dealership. I have no experience in diesels but I am a 20yr A tech. Have a 2016 model Ranger with a 3 cylinder Kohler diesel motor. Diesel motor was consuming oil and the main issue was the motor won't shut off with the key. When the key was turned off it would stumble, getting progressively worse, for about 30 40 seconds then shut off. The fuel cut on the water seperator works as it should. Swapped with know good one.
The motor would shut off, however, when the fuel inlet hose was pulled off the fuel rail [after key was turned off]. After closer inspection found a sizable blemish on the fuel rail, where the oring on the pto side injector makes contact, was leaking. Replaced fuel rail and all orings. No change.
Tore down again to find a gouge in the injector well wall in the timing belt side cylinder. The gouge was right on the oring on the injector itself causing a potential leak. Polaris warrantied the head.
During head replacment the center cylinder precombustion chamber was very carboned up indicating a possible leaky injector maybe? Replaced head as per spec. Replaced orings, copper washers and spark arrestors on all injectors. Replaced head bolts and the proper head gasket, 3 hole for this one. Also replaced the timing belt all on Polaris's dime. No change!!! Still won't shut off.
I think we solved the oil consumption issue but none of us can visualize the issue and solve. Gas engine block for so many years. Lol. Any suggestions would be appreciated. Thank you.
Submitted: 6 months ago.
Category: Small Engine
Expert:  Curtis B. replied 6 months ago.
What engine model is this? The typical Kubota uses a fuel shutoff solenoid, at the injection pump. It has to have battery voltage to open the fuel and has to stay open as long as key is on. On shutoff, the solenoid would collapse and push on the injection leakage inside the injection pump housing.??? never saw a Kubota that uses a fule valve on fuel line to kill engine. Can you attach some pictures of the setup?
Expert:  Curtis B. replied 6 months ago.
Expert:  Curtis B. replied 6 months ago.
Unplug the solenoid and see if the engine dies.
Expert:  Curtis B. replied 6 months ago.
If engine dies, the solenoid is still getting voltage from somewhere!
Customer: replied 6 months ago.
It's a 1028 cc 3 cylinder. Mechanical injection. No typical injection pump. The injectors are driven off of the cam and operate as the individual pumps. Fuel pressure is low psi lifter pump to a water seperator that has a simple cut solenoid then to the fuel rail. The solenoid has been tested.
Expert:  Curtis B. replied 6 months ago.
Is this the type solenoid it has, in the end of the block, where the injector lines come from? You did see the link?
Customer: replied 6 months ago.
Yes. It has a typical solenoid, on the water seperator. Its a generic water seperator used on all types of stuff. There are no injector lines though. There is no injector pump. They are mechanical injectors. Do you have experience with a mechanicaly injected diesel?
Customer: replied 6 months ago.
The solenoid has been unplugged swapped diseased all of the above. That was the first place I visited on this journey through this thing.
Customer: replied 6 months ago.
Dicected, not diseased. Darn spell check.
Expert:  Curtis B. replied 6 months ago.
I know them very well. We just don't seem to be on the same page! When you say mechanical injectors, they are under the rocker cover and not external, with high pressure lines to them? If so, they have a rack that moves the injector arms as one, and this rack has to go to an off position for the engine to kill. This is same type setup Deere uses . Never saw one from Kubota!
Customer: replied 6 months ago.
There are no high pressure fuel lines. Fuel pressure to the fuel rail at the rocker cover is around 10 psi. The pressure is created in the injector unit itself. This is a Polaris Ranger. Not a Kubota. It's a Kohler diesel motor. The injectors do have the rod connecting them for throttle purposes. The throttle is a centrifugal governed set up.
Expert:  Curtis B. replied 6 months ago.
Koher! Sorry. Kohler should have model number. But the fuel rod should be what kills the engine! It would have off position, and the governor then controls the run .???
Customer: replied 6 months ago.
When the motor dies the throttle goes to wide open. The centrifugal weights close the throttle when the motor starts and the throttle simply pushes against the centrifugal weights to increase rpm. This is not where the unit shuts itself off. It is purely mecanichal. No electrical parts.
Expert:  Curtis B. replied 6 months ago.
OK< Without model number of the engine, and no Polaris diesel manual, I will opt out. Good luck with it. sorry.
Customer: replied 6 months ago.
KDW1003 is the Kohler model number.

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