Before he kills the RTV and possibly himself:
and the dealer saying they have no idea how to adjust the valves or even mention to you that the RTV may be expereincing other problems is dissapointing from my point of view.
It may simply be a problem with the fuel having water in it or the injection pump timing which affects the fuel delivery which affects the starting and which affects the low idle performance of the Kubota RTV engine.
Kubota(IN its ultimate wisdom *&^%&*()*&^% stuuuuuupid) has been advancing the timing on the small diesel engines to to comply with the EPA and its desires for less exhaust particulates.
I would strongly suggest that he have the timing checked as 99 percent of the issue is the timing and if the timing is correct and top dead center for the number one cylinder you have a fuel problem with water and plugged filters most likely requiring new filters and the purchase of a RACOR fuel funnel to separate water out of the diesel fuel or installing a RACOR diesel fuel water separator filter.
Diesel engine valve adjustments must be done properly with the engine being absolutely DEAD COLD after 24-36 hours of non use!!!!!, or you will have huge PROBLEMS and an engine that will be smoking and barely running.
Long before I even began a thought about the valves needing adjustment for this engine I would do the following.
Add some seafoam to the fuel in the tank-1 ounce per gallon and a splash more.
Change the fuel filters- yes fuel filter(s)
Change the air filters and the inner element if it has one with new ones no you do not save the inner elements!!!!!!, they are referred to as the safety
element for the engine intake air.
Check the fuel lines both the suction line and return line to see if one of them may be collapsed or zip tied too tightly.
Check the tank vent in the filler cap.
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First:
I would contact the Kubota dealer and ask to have someone come out and
check the timing on the injection pump and if they say they dont know how to adjust the timing i would find another dealer.
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If you do not have a fuel funnel with a screen I would suggest you purchase a Racor fuel funnel water separator from
maesco.com - Mid-Atlantic Engine Supply Corp. for $30.00 USD and shipping or a funnel with a simple mesh screen.